cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A004798 Convolution of Fibonacci numbers 1,2,3,5,... with themselves.

Original entry on oeis.org

1, 4, 10, 22, 45, 88, 167, 310, 566, 1020, 1819, 3216, 5645, 9848, 17090, 29522, 50793, 87080, 148819, 253610, 431086, 731064, 1237175, 2089632, 3523225, 5930668, 9968122, 16730830, 28045221, 46954360, 78524159, 131181406, 218933030, 365044788, 608135635, 1012268592
Offset: 1

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Author

Keywords

Comments

From Emeric Deutsch, Feb 15 2010: (Start)
a(n) is the number of subwords of the form 0000 in all binary words of length n+3 that have no pair of adjacent 1's. Example: a(2)=4 because in the 13 (=A000045(7)) binary words of length 5 that have no pair of adjacent 1's, namely 00000, 00001, 00010, 00100, 00101, 01000, 01001, 01010, 10000, 10001, 10010, 10100, 10101, we have 2 + 1 + 0 + 0 + 0 + 0 + 0 + 0 + 1 + 1 + 0 + 0 + 0 = 4 subwords of the form 0000.
a(n) = Sum_{k>=0} k*A171855(n + 3,k). (End)
a(n) is the total number of 0's in all binary words of length n that have no pair of adjacent 1's. Example: a(5) = 45 because in the binary words listed in the above example there are respectively 5 + 4 + 4 + 4 + 3 + 4 + 3 + 3 + 4 + 3 + 3 + 3 + 2 = 45. - Geoffrey Critzer, Jul 22 2013

Examples

			a(6) = 45 + 22 + A000045(6+2) = 45 + 22 + 21 = 88. - _Philippe Deléham_, Jan 22 2012
		

Crossrefs

Programs

  • GAP
    List([1..40], n-> (n*Lucas(1,-1,n+3)[2] - 2*Fibonacci(n))/5); # G. C. Greubel, Jul 07 2019
  • Magma
    I:=[1,4,10,22]; [n le 4 select I[n] else 2*Self(n-1)+Self(n-2)-2*Self(n-3)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Apr 08 2018
    
  • Maple
    a:= n-> (<<0|1|0|0>, <0|0|1|0>, <0|0|0|1>, <-1|-2|1|2>>^n. <<0, 1, 4, 10>>)[1, 1]:
    seq(a(n), n=1..40);  # Alois P. Heinz, Jul 04 2013
    # Alternative:
    a := n -> n*(hypergeom([-(n+1)/2,-n/2],[-n-1],-4) - hypergeom([(1-n)/2,1-n/2],[-n], -4)): seq(simplify(a(n)), n=1..40); # Peter Luschny, Apr 10 2018
  • Mathematica
    nn=40; Drop[CoefficientList[Series[D[(1+x)/(1-y x -y x^2),y]/.y->1,{x,0,nn}],x],1] (* Geoffrey Critzer, Jul 22 2013 *)
    Table[n Fibonacci[n] + 2/5 (n LucasL[n] - Fibonacci[n]), {n, 40}] (* Vladimir Reshetnikov, Sep 27 2016 *)
    a[n_] := ListConvolve[f = Fibonacci[Range[2, n+1]], f][[1]]; Array[a, 40] (* Jean-François Alcover, Feb 15 2018 *)
    LinearRecurrence[{2, 1, -2, -1}, {1, 4, 10, 22}, 40] (* Vincenzo Librandi, Apr 08 2014 *)
  • PARI
    Vec(((1+x)/(1-x-x^2))^2+O(x^66)) \\ Joerg Arndt, Jul 04 2013
    
  • Sage
    [(n*lucas_number2(n+3,1,-1) - 2*fibonacci(n))/5 for n in (1..40)] # G. C. Greubel, Jul 07 2019
    

Formula

O.g.f.: (x+1)^2*x/(1-x-x^2)^2. - Len Smiley, Dec 11 2001
a(n) = a(n-1) + a(n-2) + Fibonacci(n+2). - Philippe Deléham, Jan 22 2012
O.g.f. is the derivative of A(x,y) with respect to y and then evaluated at y = 1, where A(x,y) is the o.g.f. for A030528. - Geoffrey Critzer, Jul 22 2013
a(n) = A001629(n+1) + A001629(n-1) + 2*A001629(n). - R. J. Mathar, Oct 30 2015
a(n) = n*Fibonacci(n) + (2/5)*(n*Lucas(n) - Fibonacci(n)) = A045925(n) + 2*A001629(n), where Lucas = A000032, Fibonacci = A000045. - Vladimir Reshetnikov, Sep 27 2016
a(n) = Sum_{i=0..floor((n+1)/2)} binomial(n+1-i,i)*(n-i). - John M. Campbell, Apr 07 2018
From Peter Luschny, Apr 10 2018: (Start)
a(n) = n*(hypergeom([-(n+1)/2, -n/2], [-n - 1], -4) - hypergeom([(1-n)/2, 1 - n/2], [-n], -4)).
a(n) = n*A000045(n+2) - A001629(n+1). (End)
E.g.f.: exp(x/2)*(35*x*cosh(sqrt(5)*x/2) + sqrt(5)*(15*x - 4)*sinh(sqrt(5)*x/2))/25. - Stefano Spezia, Dec 04 2023

A053538 Triangle: a(n,m) = ways to place p balls in n slots with m in the rightmost p slots, 0<=p<=n, 0<=m<=n, summed over p, a(n,m)= Sum_{k=0..n} binomial(k,m)*binomial(n-k,k-m), (see program line).

Original entry on oeis.org

1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 5, 5, 4, 1, 1, 8, 10, 7, 5, 1, 1, 13, 18, 16, 9, 6, 1, 1, 21, 33, 31, 23, 11, 7, 1, 1, 34, 59, 62, 47, 31, 13, 8, 1, 1, 55, 105, 119, 101, 66, 40, 15, 9, 1, 1, 89, 185, 227, 205, 151, 88, 50, 17, 10, 1, 1, 144, 324, 426, 414, 321, 213, 113, 61, 19, 11, 1, 1
Offset: 0

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Author

Wouter Meeussen, May 23 2001

Keywords

Comments

Riordan array (1/(1-x-x^2), x(1-x)/(1-x-x^2)). Row sums are A000079. Diagonal sums are A006053(n+2). - Paul Barry, Nov 01 2006
Subtriangle of the triangle given by (0, 1, 1, -1, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (1, 0, -1, 1, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938. - Philippe Deléham, Mar 05 2012
Mirror image of triangle in A208342. - Philippe Deléham, Mar 05 2012
A053538 is jointly generated with A076791 as an array of coefficients of polynomials u(n,x): initially, u(1,x)=v(1,x)=1, for n>1, u(n,x) = x*u(n-1,x) + v(n-1,x) and v(n,x) = u(n-1,x) + v(n-1,x). See the Mathematica section at A076791. - Clark Kimberling, Mar 08 2012
The matrix inverse starts
1;
-1, 1;
-1, -1, 1;
1, -2, -1, 1;
3, 1, -3, -1, 1;
1, 6, 1, -4, -1, 1;
-7, 4, 10, 1, -5, -1, 1;
-13, -13, 8, 15, 1, -6, -1, 1;
3, -31, -23, 13, 21, 1, -7, -1, 1; - R. J. Mathar, Mar 15 2013
Also appears to be the number of subsets of {1..n} containing n with k maximal anti-runs of consecutive elements increasing by more than 1. For example, the subset {1,3,6,7,11,12} has maximal anti-runs ((1,3,6),(7,11),(12)) so is counted under a(12,3). For runs instead of anti-runs we get A202064. - Gus Wiseman, Jun 26 2025

Examples

			n=4; Table[binomial[k, j]binomial[n-k, k-j], {k, 0, n}, {j, 0, n}] splits {1, 4, 6, 4, 1} into {{1, 0, 0, 0, 0}, {3, 1, 0, 0, 0}, {1, 4, 1, 0, 0}, {0, 0, 3, 1, 0}, {0, 0, 0, 0, 1}} and this gives summed by columns {5, 5, 4, 1, 1}
Triangle begins :
   1;
   1,  1;
   2,  1,  1;
   3,  3,  1, 1;
   5,  5,  4, 1, 1;
   8, 10,  7, 5, 1, 1;
  13, 18, 16, 9, 6, 1, 1;
...
(0, 1, 1, -1, 0, 0, 0, ...) DELTA (1, 0, -1, 1, 0, 0, 0, ...) begins :
  1;
  0,  1;
  0,  1,  1;
  0,  2,  1,  1;
  0,  3,  3,  1, 1;
  0,  5,  5,  4, 1, 1;
  0,  8, 10,  7, 5, 1, 1;
  0, 13, 18, 16, 9, 6, 1, 1;
		

Crossrefs

Column k = 1 is A000045.
Row sums are A000079.
Column k = 2 is A010049.
For runs instead of anti-runs we have A202064.
For integer partitions see A268193, strict A384905, runs A116674.
A034839 counts subsets by number of maximal runs.
A384175 counts subsets with all distinct lengths of maximal runs, complement A384176.
A384877 gives lengths of maximal anti-runs in binary indices, firsts A384878.
A384893 counts subsets by number of maximal anti-runs.

Programs

  • GAP
    Flat(List([0..12], n-> List([0..n], k-> Sum([0..n], j->  Binomial(j,k)*Binomial(n-j,j-k)) ))); # G. C. Greubel, May 16 2019
  • Magma
    [[(&+[Binomial(j,k)*Binomial(n-j,j-k): j in [0..n]]): k in [0..n]]: n in [0..12]]; // G. C. Greubel, May 16 2019
    
  • Maple
    a:= (n, m)-> add(binomial(k, m)*binomial(n-k, k-m), k=0..n):
    seq(seq(a(n,m), m=0..n), n=0..12);  # Alois P. Heinz, Sep 19 2013
  • Mathematica
    Table[Sum[Binomial[k, m]*Binomial[n-k, k-m], {k,0,n}], {n,0,12}, {m,0,n}]
  • PARI
    {T(n,k) = sum(j=0,n, binomial(j,k)*binomial(n-j,j-k))}; \\ G. C. Greubel, May 16 2019
    
  • Sage
    [[sum(binomial(j,k)*binomial(n-j,j-k) for j in (0..n)) for k in (0..n)] for n in (0..12)] # G. C. Greubel, May 16 2019
    

Formula

From Philippe Deléham, Mar 05 2012: (Start)
T(n,k) = T(n-1,k) + T(n-1,k-1) + T(n-2,k) - T(n-2,k-1), T(0,0) = T(1,0) = T(1,1) = 1 and T(n,k) = 0 if k<0 or if k>n.
G.f.: 1/(1-(1+y)*x-(1-y)*x^2).
Sum_{k, 0<=k<=n} T(n,k)*x^k = A077957(n), A000045(n+1), A000079(n), A001906(n+1), A007070(n), A116415(n), A084326(n+1), A190974(n+1), A190978(n+1), A190984(n+1), A190990(n+1), A190872(n+1) for x = -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 respectively. (End)

A111006 Another version of Fibonacci-Pascal triangle A037027.

Original entry on oeis.org

1, 0, 1, 0, 1, 2, 0, 0, 2, 3, 0, 0, 1, 5, 5, 0, 0, 0, 3, 10, 8, 0, 0, 0, 1, 9, 20, 13, 0, 0, 0, 0, 4, 22, 38, 21, 0, 0, 0, 0, 1, 14, 51, 71, 34, 0, 0, 0, 0, 0, 5, 40, 111, 130, 55, 0, 0, 0, 0, 0, 1, 20, 105, 233, 235, 89, 0, 0, 0, 0, 0, 0, 6, 65, 256, 474, 420, 144
Offset: 0

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Author

Philippe Deléham, Oct 02 2005

Keywords

Comments

Triangle T(n,k), 0 <= k <= n, read by rows, given by [0, 1, -1, 0, 0, 0, 0, 0, 0, 0, ...] DELTA [1, 1, -1, 0, 0, 0, 0, 0, 0, ...] where DELTA is the operator defined in A084938.
Row sums are the Jacobsthal numbers A001045(n+1) and column sums form Pell numbers A000129.
Maximal column entries: A038149 = {1, 1, 2, 5, 10, 22, ...}.
T(n,k) gives a convolved Fibonacci sequence (A001629, A001872, ...).
Triangle read by rows: T(n,n-k) is the number of ways to tile a 2 X n rectangle with k pieces of 2 X 2 tiles and n-2k pieces of 1 X 2 tiles (0 <= k <= floor(n/2)). - Philippe Deléham, Feb 17 2014
Diagonal sums are A013979(n). - Philippe Deléham, Feb 17 2014
T(n,k) is the number of ways to tile a 2 X n rectangle with k pieces of 2 X 2 tiles and 1 X 2 tiles. - Emeric Deutsch, Aug 14 2014

Examples

			Triangle begins:
  1;
  0, 1;
  0, 1, 2;
  0, 0, 2, 3;
  0, 0, 1, 5,  5;
  0, 0, 0, 3, 10,  8;
  0, 0, 0, 1,  9, 20, 13;
  0, 0, 0, 0,  4, 22, 38,  21;
  0, 0, 0, 0,  1, 14, 51,  71,  34;
  0, 0, 0, 0,  0,  5, 40, 111, 130,  55;
  0, 0, 0, 0,  0,  1, 20, 105, 233, 235,  89;
  0, 0, 0, 0,  0,  0,  6,  65, 256, 474, 420, 144;
		

Crossrefs

Cf. A000045, A000129, A001045, A037027, A038112, A038149, A084938, A128100 (reversed version).
Some other Fibonacci-Pascal triangles: A027926, A036355, A037027, A074829, A105809, A109906, A114197, A162741, A228074.

Programs

  • Haskell
    a111006 n k = a111006_tabl !! n !! k
    a111006_row n = a111006_tabl !! n
    a111006_tabl =  map fst $ iterate (\(us, vs) ->
       (vs, zipWith (+) (zipWith (+) ([0] ++ us ++ [0]) ([0,0] ++ us))
                        ([0] ++ vs))) ([1], [0,1])
    -- Reinhard Zumkeller, Aug 15 2013

Formula

T(0, 0) = 1, T(n, k) = 0 for k < 0 or for n < k, T(n, k) = T(n-1, k-1) + T(n-2, k-1) + T(n-2, k-2).
T(n, k) = A037027(k, n-k). T(n, n) = A000045(n+1). T(3n, 2n) = (n+1)*A001002(n+1) = A038112(n).
G.f.: 1/(1-yx(1-x)-x^2*y^2). - Paul Barry, Oct 04 2005
Sum_{k=0..n} x^k*T(n,k) = (-1)^n*A053524(n+1), (-1)^n*A083858(n+1), (-1)^n*A002605(n), A033999(n), A000007(n), A001045(n+1), A083099(n) for x = -4, -3, -2, -1, 0, 1, 2 respectively. - Philippe Deléham, Dec 02 2006
Sum_{k=0..n} T(n,k)*x^(n-k) = A053404(n), A015447(n), A015446(n), A015445(n), A015443(n), A015442(n), A015441(n), A015440(n), A006131(n), A006130(n), A001045(n+1), A000045(n+1) for x = 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 respectively. - Philippe Deléham, Feb 17 2014

A281205 T(n,k)=Number of nXk 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

Original entry on oeis.org

0, 0, 0, 1, 2, 0, 2, 14, 10, 0, 5, 28, 56, 38, 0, 10, 52, 98, 168, 130, 0, 20, 94, 176, 270, 448, 420, 0, 38, 166, 310, 470, 676, 1120, 1308, 0, 71, 290, 537, 804, 1141, 1588, 2688, 3970, 0, 130, 502, 922, 1358, 1906, 2602, 3604, 6272, 11822, 0, 235, 864, 1573, 2284, 3137
Offset: 1

Views

Author

R. H. Hardin, Jan 17 2017

Keywords

Comments

Table starts
.0.....0.....1.....2.....5....10.....20.....38.....71....130....235.....420
.0.....2....14....28....52....94....166....290....502....864...1480....2526
.0....10....56....98...176...310....537....922...1573...2672...4524....7640
.0....38...168...270...470...804...1358...2284...3834...6432..10786...18080
.0...130...448...676..1141..1906...3137...5160...8510..14084..23379...38894
.0...420..1120..1588..2602..4248...6838..11010..17840..29120..47838...78978
.0..1308..2688..3604..5712..9118..14375..22700..36144..58168..94524..154800
.0..3970..6272..7960.12208.19026..29416..45614..71452.113388.182228..295950
.0.11822.14336.17254.25577.38916..58984..89916.138676.217124.345089..555674
.0.34690.32256.36848.52784.78356.116466.174558.265278.409976.644568.1028978

Examples

			Some solutions for n=4 k=4
..0..1..0..1. .0..1..0..1. .0..1..0..1. .0..0..1..1. .0..1..0..1
..0..1..1..1. .0..1..0..0. .1..1..0..1. .1..0..1..0. .0..1..0..0
..0..1..0..0. .0..1..0..1. .0..1..0..1. .1..0..1..0. .1..0..1..1
..0..1..1..0. .0..1..0..0. .0..1..0..0. .0..1..0..1. .1..0..0..1
		

Crossrefs

Row 1 is A001629(n-1).

Formula

Empirical for column k:
k=1: a(n) = a(n-1)
k=2: a(n) = 6*a(n-1) -11*a(n-2) +6*a(n-3) -a(n-4)
k=3: a(n) = 4*a(n-1) -4*a(n-2) for n>3
k=4: a(n) = 2*a(n-1) +3*a(n-2) -4*a(n-3) -6*a(n-4) +2*a(n-5) +4*a(n-6) -a(n-8)
k=5: a(n) = 4*a(n-1) -4*a(n-2) -2*a(n-4) +4*a(n-5) -a(n-8)
k=6: [order 12]
k=7: [order 12]
Empirical for row n:
n=1: a(n) = 2*a(n-1) +a(n-2) -2*a(n-3) -a(n-4)
n=2: a(n) = 3*a(n-1) -a(n-2) -3*a(n-3) +a(n-4) +a(n-5) for n>7
n=3: a(n) = 3*a(n-1) -a(n-2) -3*a(n-3) +a(n-4) +a(n-5) for n>8
n=4: a(n) = 4*a(n-1) -4*a(n-2) -2*a(n-3) +4*a(n-4) -a(n-6) for n>10
n=5: a(n) = 4*a(n-1) -4*a(n-2) -2*a(n-3) +4*a(n-4) -a(n-6) for n>11
n=6: a(n) = 4*a(n-1) -4*a(n-2) -2*a(n-3) +4*a(n-4) -a(n-6) for n>12
n=7: a(n) = 4*a(n-1) -4*a(n-2) -2*a(n-3) +4*a(n-4) -a(n-6) for n>13

A006478 a(n) = a(n-1) + a(n-2) + F(n) - 1, a(0) = a(1) = 0, where F() = Fibonacci numbers A000045.

Original entry on oeis.org

0, 0, 0, 1, 3, 8, 18, 38, 76, 147, 277, 512, 932, 1676, 2984, 5269, 9239, 16104, 27926, 48210, 82900, 142055, 242665, 413376, 702408, 1190808, 2014608, 3401833, 5734251, 9650312, 16216602, 27213182, 45608092, 76345851, 127656829, 213230144, 355817324, 593205284
Offset: 0

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Author

Keywords

Comments

Partial sums of A001629.
Number of edges in the Fibonacci hypercube FQ(n-2) (defined in the Rispoli and Cosares reference). - Emeric Deutsch, Oct 06 2014
Circuit rank (cyclomatic number) of the n-Fibonacci cube graph. - Eric W. Weisstein, Sep 05 2017

Examples

			G.f. = x^3 + 3*x^4 + 8*x^5 + 18*x^6 + 38*x^7 + 76*x^8 + 147*x^9 + 277*x^10 + ...
		

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Haskell
    a006478 n = a006478_list !! (n-3)
    a006478_list = scanl1 (+) $ drop 2 a001629_list
    -- Reinhard Zumkeller, Sep 12 2015
  • Maple
    A006478 := proc(n)
      1 + ((n-5)*combinat[fibonacci](n-1)+(3*n-8)*combinat[fibonacci](n)) / 5;
    end proc:
    seq(A006478(n),n=0..20) ; # R. J. Mathar, Jun 12 2018
  • Mathematica
    CoefficientList[Series[x^3/((1 - x) (1 - x - x^2)^2), {x, 0, 50}], x] (* Vincenzo Librandi, Mar 13 2014 *)
    LinearRecurrence[{3, -1, -3, 1, 1}, {0, 0, 0, 1, 3, 8}, 20] (* Eric W. Weisstein, Sep 05 2017 *)
    Table[1 + (2 (n + 1) Fibonacci[n] + n Fibonacci[n + 1])/5 - Fibonacci[n + 2], {n, 0, 20}] (* Eric W. Weisstein, Sep 05 2017 *)
  • PARI
    {a(n) = if( n<0, polcoeff( x^2 / ((1 - x) * (1 + x - x^2)^2) + x * O(x^-n), -n), polcoeff( x^3 / ((1 - x) * (1 - x - x^2)^2) + x * O(x^n), n))}; /* Michael Somos, Mar 11 2014 */
    

Formula

a(n) - a(n-1) = A001629(n-1).
a(n) = 1 + ((n-5)*F(n-1) + (3*n-8)*F(n))/5.
G.f.: x^3/((1-x)*(1-x-x^2)^2). - Simon Plouffe in his 1992 dissertation
a(n) = Sum_{k=0..n-1} Sum_{i=0..k} F(i)*F(k-i). - Benoit Cloitre, Jan 26 2003
a(n) = A175722(-2-n). - Michael Somos, Mar 11 2014
a(n) = 3*a(n-1) - a(n-2) - 3*a(n-3) + a(n-4) + a(n-5). - Eric W. Weisstein, Sep 05 2017
E.g.f.: exp(x) + exp(x/2)*(5*(3*x - 5)*cosh(sqrt(5)*x/2) + sqrt(5)*(5*x - 11)*sinh(sqrt(5)*x/2))/25. - Stefano Spezia, Jul 24 2022

Extensions

a(0)-a(2) added and offset changed - N. J. A. Sloane, Jun 19 2021
Programs and b-file adapted by Georg Fischer, Jun 21 2021

A067330 Triangle read by rows of incomplete convolutions of Fibonacci numbers F(n+1) = A000045(n+1), n>=0.

Original entry on oeis.org

1, 1, 2, 2, 3, 5, 3, 5, 7, 10, 5, 8, 12, 15, 20, 8, 13, 19, 25, 30, 38, 13, 21, 31, 40, 50, 58, 71, 21, 34, 50, 65, 80, 96, 109, 130, 34, 55, 81, 105, 130, 154, 180, 201, 235, 55, 89, 131, 170, 210, 250, 289, 331, 365, 420, 89, 144, 212, 275, 340, 404, 469, 532, 600, 655, 744, 144, 233, 343, 445
Offset: 0

Views

Author

Wolfdieter Lang, Feb 15 2002

Keywords

Comments

The diagonals d>=0 (d=0: main diagonal) give convolutions of Fibonacci numbers F(n+1), n>=0, with those with d-shifted index: a(d+n,d)=sum(F(k+1)*F(d+n+1-k),k=0..n), n>=0.
The row polynomials p(n,x) := sum(a(n,m)*x^m,m=0..n) are generated by A(x*z)*(A(z)-x*A(x*z))/(1-x), with A(x) := 1/(1-x-x^2) (g.f. Fibonacci F(n+1), n>=0).
The diagonals give A001629(n+2), A023610, A067331-4, A067430-1, A067977-8 for d= n-m= 0..9, respectively.
A row with n terms = the dot product of vectors with n terms: (1,1,2,3,...)dot(...3,2,1,1) with carryovers; such that (3, 5, 7, 10) = (1*3=3), (1*2+3=5), (2*1+5=7), (3*1+7=10).

Examples

			{1}; {1,2}; {2,3,5}; {3,5,7,10}; ...; p(2,n)= 2+3*x+5*x^2.
		

Crossrefs

Cf. A067418 (triangle with rows read backwards).

Programs

  • Mathematica
    Table[Sum[Fibonacci[k + 1] Fibonacci[n - k + 1], {k, 0, m}], {n, 0, 11}, {m, 0, n}] // Flatten (* Michael De Vlieger, Apr 11 2016 *)

Formula

a(n, m)= sum(F(k+1)*F(n-k+1), k=0..m), n>=m>=0, else 0.
a(n, m)= (((3*m+5)*F(m+1)+(m+1)*F(m))*F(n-m+1)+(m*F(m+1)+2*(m+1)*F(m))*F(n-m))/5.
G.f. for diagonals d=n-m>=0: (x^d)*(F(d+1)+F(d)*x)/(1-x-x^2)^2, with F(n) := A000045(n) (Fibonacci).
a(n, m) = ((-1)^m*F(n-2*m-1)+m*L(n+2)+5*F(n)+4*F(n-1))/5, with F(-n) = (-1)^(n+1)*F(n), hence a(n, m) = (2*(m+1)*L(n+2)-A067979(n, m))/5, n>=m>=0. - Ehren Metcalfe, Apr 11 2016

A067418 Triangle A067330 with rows read backwards.

Original entry on oeis.org

1, 2, 1, 5, 3, 2, 10, 7, 5, 3, 20, 15, 12, 8, 5, 38, 30, 25, 19, 13, 8, 71, 58, 50, 40, 31, 21, 13, 130, 109, 96, 80, 65, 50, 34, 21, 235, 201, 180, 154, 130, 105, 81, 55, 34, 420, 365, 331, 289, 250, 210, 170, 131, 89, 55, 744, 655, 600, 532, 469, 404, 340, 275, 212, 144, 89, 1308, 1164, 1075, 965
Offset: 0

Views

Author

Wolfdieter Lang, Feb 15 2002

Keywords

Comments

The column m (without leading 0's) gives the convolution of Fibonacci numbers F(n+1) := A000045(n+1), n>=0, with those with m-shifted index: a(n+m,m)=sum(F(k+1)*F(m+n+1-k),k=0..n), n>=0, m=0,1,...
The row polynomials p(n,x) := sum(a(n,m)*x^m,m=0..n) are generated by A(z)*(A(z)-x*A(x*z))/(1-x), with A(x) := 1/(1-x-x^2) (g.f. for Fibonacci F(n+1), n>=0).
The columns give A001629(n+2), A023610, A067331-4, A067430-1, A067977-8 for m= 0..9, respectively. Row sums give A067988.

Examples

			{1}; {2,1}; {5,3,2}; {10,7,5,3}; ...; p(2,n)=5+3*x+2*x^2.
		

Programs

  • Mathematica
    Reverse /@ Table[Sum[Fibonacci[k + 1] Fibonacci[n - k + 1], {k, 0, m}], {n, 0, 11}, {m, 0, n}] // Flatten (* Michael De Vlieger, Apr 11 2016 *)

Formula

a(n, m)=A067330(n, n-m), n>=m>=0, else 0.
a(n, m)= (((3*(n-m)+5)*F(n-m+1)+(n-m+1)*F(n-m))*F(m+1)+((n-m)*F(n-m+1)+2*(n-m+1)*F(n-m))*F(m))/5.
G.f. for column m=0, 1, ...: (x^m)*(F(m+1)+F(m)*x)/(1-x-x^2)^2, with F(m) := A000045(m) (Fibonacci).
a(n, m) = ((-1)^m*F(n-2*m+1)-m*L(n+2)+n*L(n+2)+5*F(n)+4*F(n-1))/5, with F(-n) = (-1)^(n+1)*F(n), hence a(n, m) = (2*(n-m+1)*L(n+2)-A067990(n, m))/5, n>=m>=0. - Ehren Metcalfe, Apr 11 2016

A268886 T(n,k)=Number of nXk binary arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two exactly once.

Original entry on oeis.org

0, 1, 0, 2, 5, 0, 5, 14, 20, 0, 10, 54, 84, 71, 0, 20, 158, 501, 462, 235, 0, 38, 475, 2190, 4133, 2418, 744, 0, 71, 1340, 9996, 27130, 31956, 12252, 2285, 0, 130, 3740, 42362, 186732, 317966, 236960, 60666, 6865, 0, 235, 10204, 178400, 1187838, 3283890
Offset: 1

Views

Author

R. H. Hardin, Feb 15 2016

Keywords

Comments

Table starts
.0.....1.......2.........5..........10............20..............38
.0.....5......14........54.........158...........475............1340
.0....20......84.......501........2190..........9996...........42362
.0....71.....462......4133.......27130........186732.........1187838
.0...235....2418.....31956......317966.......3283890........31427480
.0...744...12252....236960.....3596174......55491832.......800733668
.0..2285...60666...1706732....39670270.....911930096.....19876401224
.0..6865..295230..12034000...429588382...14681855846....483987898760
.0.20284.1417452..83485488..4585939726..232688402028..11611969197776
.0.59155.6732102.571836176.48401059362.3642322709900.275345016177616

Examples

			Some solutions for n=4 k=4
..0..1..0..0. .0..0..0..0. .0..0..1..0. .0..0..0..0. .0..1..0..0
..0..0..0..1. .0..1..0..1. .1..0..0..1. .0..0..1..1. .0..1..0..0
..0..0..1..0. .1..0..0..0. .1..0..0..0. .0..0..0..0. .0..1..0..0
..1..0..1..0. .1..0..0..1. .1..1..0..1. .0..1..0..0. .1..0..0..0
		

Crossrefs

Column 2 is A054444(n-1).
Row 1 is A001629.

Formula

Empirical for column k:
k=1: a(n) = a(n-1)
k=2: a(n) = 6*a(n-1) -11*a(n-2) +6*a(n-3) -a(n-4)
k=3: a(n) = 10*a(n-1) -31*a(n-2) +30*a(n-3) -9*a(n-4)
k=4: a(n) = 16*a(n-1) -88*a(n-2) +200*a(n-3) -208*a(n-4) +96*a(n-5) -16*a(n-6) for n>7
k=5: [order 8] for n>9
k=6: [order 10] for n>12
k=7: [order 14] for n>16
Empirical for row n:
n=1: a(n) = 2*a(n-1) +a(n-2) -2*a(n-3) -a(n-4)
n=2: a(n) = 2*a(n-1) +5*a(n-2) -4*a(n-3) -11*a(n-4) -6*a(n-5) -a(n-6)
n=3: [order 9]
n=4: [order 16]
n=5: [order 26]
n=6: [order 42]
n=7: [order 68]

A269011 T(n,k)=Number of nXk binary arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two exactly once.

Original entry on oeis.org

0, 1, 0, 2, 4, 0, 5, 8, 15, 0, 10, 36, 46, 48, 0, 20, 88, 305, 224, 145, 0, 38, 272, 1078, 2136, 1066, 420, 0, 71, 696, 4948, 10976, 14240, 4952, 1183, 0, 130, 1900, 18210, 73568, 109058, 91048, 22654, 3264, 0, 235, 4856, 73277, 390064, 1049588, 1053432, 566656
Offset: 1

Views

Author

R. H. Hardin, Feb 17 2016

Keywords

Comments

Table starts
.0.....1.......2.........5.........10...........20.............38
.0.....4.......8........36.........88..........272............696
.0....15......46.......305.......1078.........4948..........18210
.0....48.....224......2136......10976........73568.........390064
.0...145....1066.....14240.....109058......1049588........8134304
.0...420....4952.....91048....1053432.....14382480......164351184
.0..1183...22654....566656...10002542....192100836.....3258530608
.0..3264..102416...3456320...93733440...2516546784....63679868768
.0..8865..458674..20760192..869397882..32481770852..1230707111424
.0.23780.2038328.123186784.7996744280.414339126768.23573013881888

Examples

			Some solutions for n=4 k=4
..1..1..0..0. .0..0..1..0. .1..0..1..1. .0..1..0..0. .0..0..0..0
..0..0..0..1. .0..0..1..0. .1..0..0..0. .0..0..1..0. .1..0..0..0
..0..0..0..0. .1..0..0..0. .1..0..0..1. .0..0..1..0. .0..1..0..0
..0..1..0..1. .0..0..1..1. .0..0..0..0. .0..0..0..0. .0..1..0..0
		

Crossrefs

Column 2 is A093967.
Row 1 is A001629.

Formula

Empirical for column k:
k=1: a(n) = a(n-1)
k=2: a(n) = 4*a(n-1) -2*a(n-2) -4*a(n-3) -a(n-4)
k=3: a(n) = 10*a(n-1) -31*a(n-2) +24*a(n-3) +21*a(n-4) -18*a(n-5) -9*a(n-6)
k=4: a(n) = 12*a(n-1) -40*a(n-2) +8*a(n-3) +92*a(n-4) -32*a(n-5) -64*a(n-6) for n>7
k=5: [order 12]
k=6: [order 14]
k=7: [order 24] for n>25
Empirical for row n:
n=1: a(n) = 2*a(n-1) +a(n-2) -2*a(n-3) -a(n-4)
n=2: a(n) = 2*a(n-1) +5*a(n-2) -6*a(n-3) -9*a(n-4)
n=3: a(n) = 4*a(n-1) +8*a(n-2) -34*a(n-3) -16*a(n-4) +60*a(n-5) -25*a(n-6)
n=4: [order 8]
n=5: [order 14]
n=6: [order 20]
n=7: [order 32]

A210034 Triangle of coefficients of polynomials v(n,x) jointly generated with A210033; see the Formula section.

Original entry on oeis.org

1, 2, 1, 4, 2, 1, 7, 5, 2, 1, 12, 10, 6, 2, 1, 20, 20, 13, 7, 2, 1, 33, 38, 29, 16, 8, 2, 1, 54, 71, 60, 39, 19, 9, 2, 1, 88, 130, 122, 86, 50, 22, 10, 2, 1, 143, 235, 241, 187, 116, 62, 25, 11, 2, 1, 232, 420, 468, 392, 267, 150, 75, 28, 12, 2, 1, 376, 744, 894, 806
Offset: 1

Views

Author

Clark Kimberling, Mar 16 2012

Keywords

Comments

For a discussion and guide to related arrays, see A208510.
From Gus Wiseman, Jun 29 2025: (Start)
This appears to be the number of subsets of {1..n} with k>0 maximal anti-runs (sequences of consecutive elements increasing by more than 1). For example, the subset {1,2,4,5} has maximal anti-runs ((1),(2,4),(5)) so is counted under T(5,3). Row n = 5 counts the following:
{1} {1,2} {1,2,3} {1,2,3,4} {1,2,3,4,5}
{2} {2,3} {2,3,4} {2,3,4,5}
{3} {3,4} {3,4,5}
{4} {4,5} {1,2,3,5}
{5} {1,2,4} {1,2,4,5}
{1,3} {1,2,5} {1,3,4,5}
{1,4} {1,3,4}
{1,5} {1,4,5}
{2,4} {2,3,5}
{2,5} {2,4,5}
{3,5}
{1,3,5}
For runs instead of anti-runs we have A034839, with n A202064. For reversed partitions instead of subsets we have A268193. (End)

Examples

			First five rows:
  1
  2    1
  4    2    1
  7    5    2   1
  12   10   6   2   1
First three polynomials v(n,x): 1, 2 + x, 4 + 2*x + x^2.
		

Crossrefs

Column k = 1 is A000071.
Row sums are A000225.
Column k = 2 is A001629.
Column k = 3 is A055243.
The version including k = 0 is A384893.
A034839 counts subsets by number of maximal runs, see also A202023, A202064.
A384175 counts subsets with all distinct lengths of maximal runs, complement A384176.
A384877 gives lengths of maximal anti-runs of binary indices, firsts A384878.

Programs

  • Mathematica
    u[1, x_] := 1; v[1, x_] := 1; z = 16;
    u[n_, x_] := u[n - 1, x] + v[n - 1, x] + 1;
    v[n_, x_] := u[n - 1, x] + x*v[n - 1, x] + 1;
    Table[Expand[u[n, x]], {n, 1, z/2}]
    Table[Expand[v[n, x]], {n, 1, z/2}]
    cu = Table[CoefficientList[u[n, x], x], {n, 1, z}];
    TableForm[cu]
    Flatten[%]    (* A210033 *)
    Table[Expand[v[n, x]], {n, 1, z}]
    cv = Table[CoefficientList[v[n, x], x], {n, 1, z}];
    TableForm[cv]
    Flatten[%]    (* A210034 *)

Formula

u(n,x)=u(n-1,x)+v(n-1,x)+1,
v(n,x)=u(n-1,x)+x*v(n-1,x)+1,
where u(1,x)=1, v(1,x)=1.
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