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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A023548 Convolution of natural numbers >= 2 and Fibonacci numbers.

Original entry on oeis.org

2, 5, 11, 21, 38, 66, 112, 187, 309, 507, 828, 1348, 2190, 3553, 5759, 9329, 15106, 24454, 39580, 64055, 103657, 167735, 271416, 439176, 710618, 1149821, 1860467, 3010317, 4870814, 7881162, 12752008, 20633203, 33385245, 54018483, 87403764, 141422284
Offset: 1

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Author

Keywords

Comments

Minimal cost of maximum height Huffman tree of size n for strictly "worst case height" sequences. (A strictly "worst case height" sequence generates only maximum height Huffman trees; a non-strictly "worst case height" sequence can generate also non-maximum height Huffman trees.) - Alex Vinokur (alexvn(AT)barak-online.net), Oct 26 2004
Record-positions for A107910: A107910(a(n+2)) = A005578(n), A107910(m) < A005578(n) for m < a(n+2). - Reinhard Zumkeller, May 28 2005
From Jianing Song, Apr 28 2025: (Start)
For n >= 4, a(n-3) is the number of subsets of {1,2,...,n} with at least 2 elements that contain no consecutive elements modulo n. Note that:
- the number of subsets of {1,2,...,n} with k elements such that the difference of successive elements is at least 2 is binomial(n+1-k,k);
- the number of such subsets of {1,2,...,n} with k elements that contain both 1 and n is equal to the number of such subsets of {3,...,n-2} with k-2 elements, which is binomial(n-3-(k-2),k-2),
hence a(n) = Sum_{k=2..floor((n+1)/2)} binomial(n+1-k,k) - Sum_{k=0..floor((n-3)/2)} binomial(n-3-k,k) = (F(n+2) - binomial(n+1,0) - binomial(n,1)) - F(n-2) = F(n+1) + F(n-1) - (n+1).
If subsets of {1,2,...,n} are only required to contain no consecutive elements, then the result is A001924(n-2). (End)

Crossrefs

Antidiagonal sums of A292030.

Programs

  • GAP
    List([1..40], n-> Lucas(1,-1,n+3)[2] -n-4); # G. C. Greubel, Jul 08 2019
  • Magma
    [4*(Fibonacci(n+1)-1)+3*Fibonacci(n)-n: n in [1..40]]; // Vincenzo Librandi, Sep 16 2017
    
  • Mathematica
    Table[4(Fibonacci[n+1] -1) +3Fibonacci[n] -n, {n, 40}] (* Vincenzo Librandi, Sep 16 2017 *)
  • PARI
    a(n) = 4*fibonacci(n+1) + 3*fibonacci(n) - n - 4; \\ Michel Marcus, Sep 08 2016
    
  • PARI
    Vec(x*(2-x) / ((1-x-x^2)*(1-x)^2) + O(x^40)) \\ Colin Barker, Mar 11 2017
    
  • Sage
    [lucas_number2(n+3,1,-1) -n-4 for n in (1..40)] # G. C. Greubel, Jul 08 2019
    

Formula

From Wolfdieter Lang: (Start)
Convolution of natural numbers n >= 1 with Lucas numbers (A000032).
a(n) = 4*(F(n+1) - 1) + 3*F(n) - n, F(n)=A000045 (Fibonacci).
G.f.: x*(2-x)/((1-x-x^2)*(1-x)^2). (End)
For n >= 1, a(n) = L(n+3) - (n+4), where L(n) are Lucas numbers. - Mario Catalani (mario.catalani(AT)unito.it), Jul 22 2004
a(n) = F(n+4) + F(n+2) - (n+4) for n >= 1. - Alex Vinokur (alexvn(AT)barak-online.net), Oct 26 2004 [Offset corrected by Jianing Song, Apr 28 2025]
a(n) = (-4 + (2^(-n)*((1-sqrt(5))^n*(-5+2*sqrt(5)) + (1+sqrt(5))^n*(5+2*sqrt(5)))) / sqrt(5) - n). - Colin Barker, Mar 11 2017
a(n) = Sum_{i=1..n} C(n-i+2,i+1) + C(n-i+1,i). - Wesley Ivan Hurt, Sep 13 2017
E.g.f.: 2*exp(x/2)*(2*cosh((sqrt(5)*x)/2) + sqrt(5)*sinh((sqrt(5)*x)/2)) - exp(x)*(4 + x). - Stefano Spezia, May 21 2025

A105809 Riordan array (1/(1 - x - x^2), x/(1 - x)).

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 3, 4, 3, 1, 5, 7, 7, 4, 1, 8, 12, 14, 11, 5, 1, 13, 20, 26, 25, 16, 6, 1, 21, 33, 46, 51, 41, 22, 7, 1, 34, 54, 79, 97, 92, 63, 29, 8, 1, 55, 88, 133, 176, 189, 155, 92, 37, 9, 1, 89, 143, 221, 309, 365, 344, 247, 129, 46, 10, 1, 144, 232, 364, 530, 674, 709, 591
Offset: 0

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Author

Paul Barry, May 04 2005

Keywords

Comments

Previous name was: A Fibonacci-Pascal matrix.
From Wolfdieter Lang, Oct 04 2014: (Start)
In the column k of this triangle (without leading zeros) is the k-fold iterated partial sums of the Fibonacci numbers, starting with 1. A000045(n+1), A000071(n+3), A001924(n+1), A014162(n+1), A014166(n+1), ..., n >= 0. See the Riordan property.
For a combinatorial interpretation of these iterated partial sums see the H. Belbachir and A. Belkhir link. There table 1 shows in the rows these columns. In their notation (with r = k) f^(k)(n) = T(k, n+k).
The A-sequence of this Riordan triangle is [1, 1] (see the recurrence for T(n, k), k >= 1, given in the formula section). The Z-sequence is A165326 = [1, repeat(1, -1)]. See the W. Lang link under A006232 for Riordan A- and Z-sequences. (End)

Examples

			The triangle T(n,k) begins:
n\k   0   1   2    3    4    5    6    7    8   9  10 11 12 13 ...
0:    1
1:    1   1
2:    2   2   1
3:    3   4   3    1
4:    5   7   7    4    1
5:    8  12  14   11    5    1
6:   13  20  26   25   16    6    1
7:   21  33  46   51   41   22    7    1
8:   34  54  79   97   92   63   29    8    1
9:   55  88 133  176  189  155   92   37    9   1
10:  89 143 221  309  365  344  247  129   46  10   1
11: 144 232 364  530  674  709  591  376  175  56  11  1
12: 233 376 596  894 1204 1383 1300  967  551 231  67 12  1
13: 377 609 972 1490 2098 2587 2683 2267 1518 782 298 79 13  1
... reformatted and extended - _Wolfdieter Lang_, Oct 03 2014
------------------------------------------------------------------
Recurrence from Z-sequence (see a comment above): 8 = T(0,5) = (+1)*5 + (+1)*7 + (-1)*7 + (+1)*4 + (-1)*1 = 8. - _Wolfdieter Lang_, Oct 04 2014
		

Crossrefs

Cf. A165326 (Z-sequence), A027934 (row sums), A010049(n+1) (antidiagonal sums), A212804 (alternating row sums), inverse is A105810.
Some other Fibonacci-Pascal triangles: A027926, A036355, A037027, A074829, A109906, A111006, A114197, A162741, A228074.

Programs

  • Haskell
    a105809 n k = a105809_tabl !! n !! k
    a105809_row n = a105809_tabl !! n
    a105809_tabl = map fst $ iterate
       (\(u:_, vs) -> (vs, zipWith (+) ([u] ++ vs) (vs ++ [0]))) ([1], [1,1])
    -- Reinhard Zumkeller, Aug 15 2013
  • Maple
    T := (n,k) -> `if`(n=0,1,binomial(n,k)*hypergeom([1,k/2-n/2,k/2-n/2+1/2], [k+1,-n], -4)); for n from 0 to 13 do seq(simplify(T(n,k)),k=0..n) od; # Peter Luschny, Oct 10 2014
  • Mathematica
    T[n_, k_] := Sum[Binomial[n-j, k+j], {j, 0, n}]; Table[T[n, k], {n, 0, 11}, {k, 0, n}] (* Jean-François Alcover, Jun 11 2019 *)

Formula

Riordan array (1/(1-x-x^2), x/(1-x)).
Triangle T(n, k) = Sum_{j=0..n} binomial(n-j, k+j); T(n, 0) = A000045(n+1);
T(n, m) = T(n-1, m-1) + T(n-1, m).
T(n, k) = Sum_{j=0..n} binomial(j, n+k-j). - Paul Barry, Oct 23 2006
G.f. of row polynomials Sum_{k=0..n} T(n, k)*x^k is (1 - z)/((1 - z - z^2)*(1 - (1 + x)*z)) (Riordan property). - Wolfdieter Lang, Oct 04 2014
T(n, k) = binomial(n, k)*hypergeom([1, k/2 - n/2, k/2 - n/2 + 1/2],[k + 1, -n], -4) for n > 0. - Peter Luschny, Oct 10 2014
From Wolfdieter Lang, Feb 13 2025: (Start)
Array A(k, n) = Sum_{j=0..n} F(j+1)*binomial(k-1+n-j, k-1), k >= 0, n >= 0, with F = A000045, (from Riordan triangle k-th convolution in columns without leading 0s).
A(k, n) = F(n+1+2*k) - Sum_{j=0..k-1} F(2*(k-j)-1) * binomial(n+1+j, j), (from iteration of partial sums).
Triangle T(n, k) = A(k, n-k) = Sum_{j=k..n} F(n-j+1) * binomial(j-1, k-1), 0 <= k <= n.
T(n, k) = F(n+1+k) - Sum_{j=0..k-1} F(2*(k-j)-1) * binomial(n - (k-1-j), j). (End)
T(n, k) = A027926(n, n+k), for 0 <= k <= n. - Wolfdieter Lang, Mar 08 2025

Extensions

Use first formula as a more descriptive name, Joerg Arndt, Jun 08 2021

A011794 Triangle defined by T(n+1, k) = T(n, k-1) + T(n-1, k), T(n,1) = 1, T(1,k) = 1, T(2,k) = min(2,k).

Original entry on oeis.org

1, 1, 2, 1, 2, 3, 1, 3, 4, 5, 1, 3, 6, 7, 8, 1, 4, 7, 11, 12, 13, 1, 4, 10, 14, 19, 20, 21, 1, 5, 11, 21, 26, 32, 33, 34, 1, 5, 15, 25, 40, 46, 53, 54, 55, 1, 6, 16, 36, 51, 72, 79, 87, 88, 89, 1, 6, 21, 41, 76, 97, 125, 133, 142, 143, 144, 1, 7, 22, 57, 92, 148, 176, 212, 221, 231, 232, 233
Offset: 1

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Author

Keywords

Examples

			matrix(10,10,n,k,a(n-1,k-1))
  [ 0 0 0 0 0 0 0 0 0 0 ]
  [ 0 1 1 1 1 1 1 1 1 1 ]
  [ 0 1 2 2 2 2 2 2 2 2 ]
  [ 0 1 2 3 3 3 3 3 3 3 ]
  [ 0 1 3 4 5 5 5 5 5 5 ]
  [ 0 1 3 6 7 8 8 8 8 8 ]
Triangle begins as:
  1;
  1, 2;
  1, 2,  3;
  1, 3,  4,  5;
  1, 3,  6,  7,  8;
  1, 4,  7, 11, 12, 13;
  1, 4, 10, 14, 19, 20, 21;
  1, 5, 11, 21, 26, 32, 33, 34;
  1, 5, 15, 25, 40, 46, 53, 54, 55;
  1, 6, 16, 36, 51, 72, 79, 87, 88, 89;
		

Crossrefs

Columns include A008619 and (essentially) A055802, A055803, A055804, A055805, A055806.
Essentially a reflected version of A055801.
Sums include: A039834 (signed row), A131913 (row).

Programs

  • Magma
    function T(n,k) // T = A011794(n,k)
      if k eq 1 or n eq 1 then return 1;
      elif n eq 2 then return Min(2, k);
      else return T(n-1,k-1) + T(n-2,k);
      end if;
    end function;
    [T(n,k): k in [1..n], n in [1..15]]; // G. C. Greubel, Oct 21 2024
    
  • Mathematica
    T[n_, k_]:= T[n, k]= T[n-1, k-1] + T[n-2, k]; T[n_, 1] = 1; T[1, k_] = 1; T[2, k_] := Min[2, k]; Table[T[n, k], {n,15}, {k,n}]//Flatten (* Jean-François Alcover, Feb 26 2013 *)
  • PARI
    T(n,k)=if(n<=0 || k<=0,0, if(n<=2 || k==1, min(n,k), T(n-1,k-1)+T(n-2,k)))
    
  • SageMath
    def T(n, k): # T = A011794
        if (k==1 or n==1): return 1
        elif (n==2): return min(2,k)
        else: return T(n-1, k-1) + T(n-2, k)
    flatten([[T(n, k) for k in range(1,n+1)] for n in range(1,16)]) # G. C. Greubel, Oct 21 2024

Formula

T(n,n) = Fibonacci(n+1). - Jean-François Alcover, Feb 26 2013
From G. C. Greubel, Oct 21 2024: (Start)
Sum_{k=1..n} T(n, k) = A131913(n-1).
Sum_{k=1..n} (-1)^(k-1)*T(n, k) = A039834(n).
Sum_{k=1..floor((n+1)/2)} T(n-k+1,k) = (1/2)*((1-(-1)^n)*A074878((n+3)/2) + (1+(-1)^n)*A008466((n+6)/2)) (diagonal row sums).
Sum_{k=1..floor((n+1)/2)} (-1)^(k-1)*T(n-k+1,k) = (-1)^floor((n-1)/2)*A103609(n) + [n=1] (signed diagonal row sums). (End)

Extensions

Entry improved by comments from Michael Somos
More terms added by G. C. Greubel, Oct 21 2024

A065220 a(n) = Fibonacci(n) - n.

Original entry on oeis.org

0, 0, -1, -1, -1, 0, 2, 6, 13, 25, 45, 78, 132, 220, 363, 595, 971, 1580, 2566, 4162, 6745, 10925, 17689, 28634, 46344, 75000, 121367, 196391, 317783, 514200, 832010, 1346238, 2178277, 3524545, 5702853, 9227430, 14930316, 24157780, 39088131, 63245947, 102334115, 165580100, 267914254
Offset: 0

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Author

Henry Bottomley, Oct 22 2001

Keywords

Comments

E(n) = Fib(n+4)-(n+4): cost of maximum height Huffman tree of size n for Fibonacci sequence (Fibonacci sequence is minimizing absolutely ordered sequence of Huffman tree). - Alex Vinokur (alexvn(AT)barak-online.net), Oct 26 2004

References

  • Vinokur A.B, Huffman trees and Fibonacci numbers, Kibernetika Issue 6 (1986) 9-12 (in Russian); English translation in Cybernetics 21, Issue 6 (1986), 692-696.

Crossrefs

Programs

  • GAP
    List([0..50], n-> Fibonacci(n) - n); # G. C. Greubel, Jul 09 2019
  • Haskell
    a065220 n = a065220_list !! n
    a065220_list = zipWith (-) a000045_list [0..]
    -- Reinhard Zumkeller, Nov 06 2012
    
  • Magma
    [Fibonacci(n) - n: n in [0..50]]; // G. C. Greubel, Jul 09 2019
    
  • Maple
    a[0]:=0:a[1]:=1:for n from 2 to 50 do a[n]:=a[n-1]+a[n-2] od: seq(a[n]-n, n=0..42); # Zerinvary Lajos, Mar 20 2008
  • Mathematica
    lst={};Do[f=Fibonacci[n]-n;AppendTo[lst,f],{n,0,5!}];lst (* Vladimir Joseph Stephan Orlovsky, Mar 21 2009 *)
    Table[Fibonacci[n]-n,{n,0,50}] (* or *) LinearRecurrence[{3,-2,-1,1},{0,0,-1,-1},50] (* Harvey P. Dale, May 29 2017 *)
  • PARI
    a(n) = { fibonacci(n) - n } \\ Harry J. Smith, Oct 14 2009
    
  • Sage
    [fibonacci(n) - n for n in (0..50)] # G. C. Greubel, Jul 09 2019
    

Formula

a(n) = A000045(n) - A001477(n) = A000126(n-3) - 2 = A001924(n-4) - 1.
a(n) = a(n-1) + a(n-2) + n - 3 = a(n-1) + A000071(n-2).
G.f.: x^2*(2x-1)/((1-x-x^2)*(1-x)^2).
a(n) = Sum_{i=0..n} (i - 2)*F(n-i) for F(n) the Fibonacci sequence A000045. - Greg Dresden, Jun 01 2022

A129696 Antidiagonal sums of triangular array T defined in A014430: T(j,k) = binomial(j+1, k) - 1 for 1 <= k <= j.

Original entry on oeis.org

1, 2, 5, 9, 17, 29, 50, 83, 138, 226, 370, 602, 979, 1588, 2575, 4171, 6755, 10935, 17700, 28645, 46356, 75012, 121380, 196404, 317797, 514214, 832025, 1346253, 2178293, 3524561, 5702870, 9227447, 14930334, 24157798, 39088150, 63245966
Offset: 1

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Author

Paul Curtz, Jun 01 2007

Keywords

Comments

If T is construed as a lower triangular matrix M over the rational field, the inverse M^-1 is a lower triangular matrix containing fractions. Its row sums are the Bernoulli numbers. First column of M^-1 is 1, -1, 2/3, -1/4, -1/30, 1/12, 1/42, -1/12, ... . Multiplied by j! this gives 1, -2, 4, -6, -4, 60, 120, -3660, ... .
The Kn22 sums, see A180662 for the definition of these sums, of the 'Races with Ties' triangle A035317 lead to this sequence. - Johannes W. Meijer, Jul 20 2011
This sequence is the convolution of (1,1,2,3,5,8,13,21,...) and (1,1,2,2,3,3,4,4,5,5,...), i.e., the Fibonacci numbers (A000045) and A008619. - Clark Kimberling, May 28 2012
a(n) is the sum of the first summands over all Arndt compositions of n (see the Checa link). - Daniel Checa, Jan 01 2024

References

  • Paul Curtz, Intégration numérique des systèmes différentiels à conditions initiales. Note no. 12 du Centre de Calcul Scientifique de l'Armement, 1969.

Crossrefs

Programs

  • Magma
    m:=36; M:=ZeroMatrix(IntegerRing(), m, m); for j:=1 to m do for k:=1 to j do M[j, k]:=Binomial(j+1, k)-1; end for; end for; [ &+[ M[j-k+1, k]: k in [1..(j+1) div 2] ]: j in [1..m] ]; // Klaus Brockhaus, Jun 11 2007
    
  • Magma
    [Fibonacci(n+3)-2-Floor(n/2): n in [1..40]]; // Vincenzo Librandi, Nov 23 2014
    
  • Maple
    with(combinat): a := proc (n) options operator, arrow: fibonacci(n+3)-2-floor((1/2)*n) end proc: seq(a(n), n = 1 .. 34); # Emeric Deutsch, Nov 22 2014
  • Mathematica
    a[n_]:= a[n]= If[n<3, n, a[n-1] + a[n-2] + (n + Mod[n, 2])/2];
    Table[a[n], {n,40}] (* Jean-François Alcover, Mar 04 2013 *)
    Table[Fibonacci[n+3] -2 -Floor[n/2], {n, 100}] (* Vincenzo Librandi, Nov 23 2014 *)
  • Python
    prpr = 1
    prev = 2
    for n in range(2,100):
        print(prpr, end=", ")
        curr = prpr+prev + 1 + n//2
        prpr = prev
        prev = curr
    # Alex Ratushnyak, Jul 30 2012
    
  • SageMath
    [fibonacci(n+3) -2 -(n//2) for n in range(1,41)] # G. C. Greubel, Mar 17 2023

Formula

From Paul Barry, Jan 18 2009: (Start)
a(n) = Sum_{k=0..floor(n/2)} A000071(n-2*k+3).
a(n) = Sum_{k=0..floor(n/2)} (Sum_{j=0..n-2*k} Fibonacci(j+1)). (End)
a(n+1) = a(n-1) + a(n) + 1 + floor(n/2) for n>1, a(0)=1, a(1)=2. - Alex Ratushnyak, Jul 30 2012
From R. J. Mathar, Jul 25 2013: (Start)
G.f.: x/((1 + x)*(1 - x)^2*(1 - x - x^2)).
a(n) + a(n+1) = A001924(n+1). (End)
a(n) = Fibonacci(n+3) - 2 - floor(n/2). - Emeric Deutsch, Nov 22 2014
a(n) = (-5/4 - (-1)^n/4 + (2^(-n)*((1 - t)^n*(-2 + t) + (1 + t)^n*(2 + t)))/t + (-1 - n)/2), where t=sqrt(5). - Colin Barker, Feb 09 2017
E.g.f.: (4*exp(x/2)*(5*cosh(sqrt(5)*x/2) + 2*sqrt(5)*sinh(sqrt(5)*x/2)) - 5*(4 + x)*cosh(x) - 5*(3 + x)*sinh(x))/10. - Stefano Spezia, Apr 06 2024
a(n) = max_{k = 2^(n+1)..2^(n+2)-1} (A002487(k) - A000120(k)) (Ericksen, 2019). - Amiram Eldar, Jan 30 2025

Extensions

Edited and extended by Klaus Brockhaus, Jun 11 2007

A014162 Apply partial sum operator thrice to Fibonacci numbers.

Original entry on oeis.org

0, 1, 4, 11, 25, 51, 97, 176, 309, 530, 894, 1490, 2462, 4043, 6610, 10773, 17519, 28445, 46135, 74770, 121115, 196116, 317484, 513876, 831660, 1345861, 2177872, 3524111, 5702389, 9226935, 14929789
Offset: 0

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Author

Keywords

Comments

With offset 4, number of 132-avoiding two-stack sortable permutations which contain exactly one subsequence of type 51234.

Crossrefs

Right-hand column 6 of triangle A011794.

Programs

  • GAP
    List([0..40], n-> Fibonacci(n+6) - (n^2 + 7*n + 16)/2); # G. C. Greubel, Sep 05 2019
  • Magma
    [Fibonacci(n+6) - (n^2 + 7*n + 16)/2: n in [0..40]]; // G. C. Greubel, Sep 05 2019
    
  • Maple
    with(combinat); seq(fibonacci(n+6)-(n^2+7*n+16)*(1/2), n = 0..40); # G. C. Greubel, Sep 05 2019
  • Mathematica
    Nest[Accumulate,Fibonacci[Range[0,30]],3] (* or *) LinearRecurrence[{4,-5,1,2,-1},{0,1,4,11,25},40] (* Harvey P. Dale, Aug 19 2017 *)
  • PARI
    a(n)=fibonacci(n+6)-n*(n+7)/2-8 \\ Charles R Greathouse IV, Jun 11 2015
    
  • Sage
    [fibonacci(n+6) - (n^2 + 7*n + 16)/2 for n in (0..40)] # G. C. Greubel, Sep 05 2019
    

Formula

a(n) = Sum_{k=0..n} A000045(n-k)*k*(k+1)/2. - Benoit Cloitre, Jan 06 2003
G.f.: x/((1-x)^3*(1-x-x^2)).
From Paul Barry, Oct 07 2004: (Start)
a(n-2) = Sum_{k=0..floor(n/2)} binomial(n-k, k+3).
a(n-2) = Sum_{k=0..n} binomial(k, n-k+3). (End)
Convolution of A000045 and A000217 (Fibonacci and triangular numbers). - Ross La Haye, Nov 08 2004
a(n) = Fibonacci(n+6) - (n^2 + 7*n + 16)/2.

A136431 Hyperfibonacci square number array a(k,n) = F(n)^(k), read by ascending antidiagonals (k, n >= 0).

Original entry on oeis.org

0, 0, 1, 0, 1, 1, 0, 1, 2, 2, 0, 1, 3, 4, 3, 0, 1, 4, 7, 7, 5, 0, 1, 5, 11, 14, 12, 8, 0, 1, 6, 16, 25, 26, 20, 13, 0, 1, 7, 22, 41, 51, 46, 33, 21, 0, 1, 8, 29, 63, 92, 97, 79, 54, 34, 0, 1, 9, 37, 92, 155, 189, 176, 133, 88, 55, 0, 1, 10, 46, 129, 247, 344, 365, 309, 221, 143, 89, 0, 1
Offset: 0

Views

Author

Jonathan Vos Post, Apr 01 2008

Keywords

Comments

Main diagonal is A108081. Antidiagonal sums form A027934. - Gerald McGarvey, Oct 01 2008
Seen as triangle read by rows: T(n,0) = 1, T(n,n) = A000045(n) and for 0 < k < n: T(n,k) = T(n-1,k-1) + T(n-1,k). - Reinhard Zumkeller, Jul 16 2013

Examples

			The array F(n)^(k) begins:
.....|n=0|n=1|.n=2|.n=3|.n=4.|.n=5.|..n=6.|.n=7..|..n=8..|..n=9..|.n=10..|.in.OEIS
k=0..|.0.|.1.|..1.|..2.|...3.|...5.|....8.|...13.|....21.|....34.|....55.|.A000045
k=1..|.0.|.1.|..2.|..4.|...7.|..12.|...20.|...33.|....54.|....88.|...143.|.A000071
k=2..|.0.|.1.|..3.|..7.|..14.|..26.|...46.|...79.|...133.|...221.|...364.|.A001924
k=3..|.0.|.1.|..4.|.11.|..25.|..51.|...97.|..176.|...309.|...530.|...894.|.A014162
k=4..|.0.|.1.|..5.|.16.|..41.|..92.|..189.|..365.|...674.|..1204.|..2098.|.A014166
k=5..|.0.|.1.|..6.|.22.|..63.|.155.|..344.|..709.|..1383.|..2587.|..4685.|.A053739
k=6..|.0.|.1.|..7.|.29.|..92.|.247.|..591.|.1300.|..2683.|..5270.|..9955.|.A053295
k=7..|.0.|.1.|..8.|.37.|.129.|.376.|..967.|.2267.|..4950.|.10220.|.20175.|.A053296
k=8..|.0.|.1.|..9.|.46.|.175.|.551.|.1518.|.3785.|..8735.|.18955.|.39130.|.A053308
k=9..|.0.|.1.|.10.|.56.|.231.|.782.|.2300.|.6085.|.14820.|.33775.|.72905.|.A053309
		

Crossrefs

Programs

  • Haskell
    a136431 n k = a136431_tabl !! n !! k
    a136431_row n = a136431_tabl !! n
    a136431_tabl = map fst $ iterate h ([0], 1) where
       h (row, fib) = (zipWith (+) ([0] ++ row) (row ++ [fib]), last row)
    -- Reinhard Zumkeller, Jul 16 2013
  • Maple
    A136431 := proc(k,n) local x ; coeftayl(x/(1-x-x^2)/(1-x)^k,x=0,n) ; end: for d from 0 to 20 do for n from 0 to d do printf("%d,",A136431(d-n,n)) ; od: od: # R. J. Mathar, Apr 25 2008
  • Mathematica
    t[n_, k_] := CoefficientList[Series[x/(1 - x - x^2)/(1 - x)^k, {x, 0, n + 1}], x][[n + 1]]; Table[ t[n, k - n], {k, 0, 11}, {n, 0, k}] // Flatten
    (* To view the table above *) Table[ t[n, k], {k, 0, 9}, {n, 0, 10}] // TableForm

Formula

a(k,n) = Apply partial sum operator k times to Fibonacci numbers.
For k > 0 and n > 1, a(k,n) = a(k-1,n) + a(k,n-1). - Gerald McGarvey, Oct 01 2008

A107909 Numbers having no consecutive zeros or no consecutive ones in binary representation.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 20, 21, 22, 23, 26, 27, 29, 30, 31, 32, 33, 34, 36, 37, 40, 41, 42, 43, 45, 46, 47, 53, 54, 55, 58, 59, 61, 62, 63, 64, 65, 66, 68, 69, 72, 73, 74, 80, 81, 82, 84, 85, 86, 87, 90, 91, 93, 94, 95, 106, 107, 109, 110, 111
Offset: 0

Views

Author

Reinhard Zumkeller, May 28 2005

Keywords

Comments

Union of A003754 and A003714, complement of A107911;
a(A023548(n+2)) = A052940(n+1) for n>0;
a(A001924(n)) = A000225(n) = 2^n - 1;
a(A000126(n)) = A000079(n) = 2^n for n>0;
A107910(n) = a(n+1) - a(n).

Crossrefs

Programs

  • Perl
    foreach $n(1..100){$_=sprintf("%b",$n); print "$n\n" if !m/11/||!m/00/}
    # Ivan Neretin, May 01 2016

A152686 Partial products of the partial products of the nonzero Fibonacci numbers.

Original entry on oeis.org

1, 1, 1, 2, 12, 360, 86400, 269568000, 17662095360000, 39345496591564800000, 4820704671590339051520000000, 52567343238846954009129910272000000000, 82543717140049422917575408530662149324800000000000
Offset: 0

Views

Author

Keywords

Comments

Partial products of A003266.

Crossrefs

Programs

  • Mathematica
    Table[Product[Product[Fibonacci[k],{k,1,j}],{j,1,n}],{n,1,12}] (* Vaclav Kotesovec, May 01 2015 *)

Formula

a(n) = Product_{i=1..n} A003266(i). - R. J. Mathar, Dec 12 2008
a(n) ~ f * ((1+sqrt(5))/2)^(n*(n+1)*(n+2)/6) * C^n / 5^(n*(n+1)/4), where C = A062073 = 1.2267420107203532444176302... is the Fibonacci factorial constant and f = A253267 = 1.096414072507324423110215998844440375945929608777697938465... . - Vaclav Kotesovec, May 01 2015

Extensions

Edited by R. J. Mathar, Dec 12 2008
a(0)=1 prepended by Alois P. Heinz, Sep 14 2018

A062544 a(n) = n plus sum of previous three terms.

Original entry on oeis.org

0, 1, 3, 7, 15, 30, 58, 110, 206, 383, 709, 1309, 2413, 4444, 8180, 15052, 27692, 50941, 93703, 172355, 317019, 583098, 1072494, 1972634, 3628250, 6673403, 12274313, 22575993, 41523737, 76374072, 140473832, 258371672, 475219608, 874065145, 1607656459, 2956941247
Offset: 0

Views

Author

Henry Bottomley, Jun 26 2001

Keywords

Comments

It appears that this is the number of nonempty subsets of {1,2,...,n} with no gap of length greater than 3 (a set S has a gap of length d if a and b are in S but no x with aA119407 for the corresponding problem for gaps of length 4. - John W. Layman, Nov 02 2011
a(n-3) is the number of compositions of n with no part divisible by 3 and an odd number of parts congruent to 4 or 5 modulo 6. See Moser & Whitney reference. a(2) = 3 counts (5), (4,1), and (1,4) among the compositions of 5. - Brian Hopkins, Sep 06 2019

Examples

			a(5) = 5 + 15 + 7 + 3 = 30.
x + 3*x^2 + 7*x^3 + 15*x^4 + 30*x^5 + 58*x^6 + 110*x^7 + 206*x^8 + 383*x^9 + ...
		

Crossrefs

n plus sum of all previous terms gives A000225, n plus sum of two previous terms gives A001924, n plus previous term gives A000217, n gives A001477.
Cf. A001590 and A325473.

Programs

  • Mathematica
    Join[{c=0},a=b=0;Table[z=b+a+c+n;a=b;b=c;c=z,{n,1,40}]] (* Vladimir Joseph Stephan Orlovsky, Apr 02 2011 *)
  • PARI
    { a=a1=a2=a3=0; for (n=0, 300, write("b062544.txt", n, " ", a+=n + a2 + a3); a3=a2; a2=a1; a1=a ) } \\ Harry J. Smith, Aug 08 2009
    
  • PARI
    {a(n) = if( n<0, n = -n; polcoeff( x^4 / ((1 - x) * (1 - 2*x^3 + x^4)) + x * O(x^n), n), polcoeff( x / ((1 - x) * (1 - 2*x + x^4)) + x * O(x^n), n))} /* Michael Somos, Dec 28 2012 */

Formula

a(n) = 3*a(n-1) - 2*a(n-2) - 1*a(n-4) + 1*a(n-5). - Joerg Arndt, Apr 02 2011
a(n) = n + a(n-1) + a(n-2) + a(n-3) =(A001590(n+4) - n - 3)/2.
G.f.: x / ((1 - x) * (1 - 2*x + x^4)). a(n) = 2*a(n-1) - a(n-4) + 1. - Michael Somos, Dec 28 2012
a(n) = A325473(n+3) - (n+3). - Brian Hopkins, Sep 06 2019
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