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.

Showing 1-10 of 17 results. Next

A045891 First differences of A045623.

Original entry on oeis.org

1, 1, 3, 7, 16, 36, 80, 176, 384, 832, 1792, 3840, 8192, 17408, 36864, 77824, 163840, 344064, 720896, 1507328, 3145728, 6553600, 13631488, 28311552, 58720256, 121634816, 251658240, 520093696, 1073741824, 2214592512, 4563402752
Offset: 0

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Author

Keywords

Comments

Let M_n be the n X n matrix m_(i,j) = 3 + abs(i-j), then det(M_n) =(-1)^(n+1)*a(n+1). - Benoit Cloitre, May 28 2002
If X_1, X_2, ..., X_n are 2-blocks of a (2n+3)-set X then, for n>=1, a(n+2) is the number of (n+1)-subsets of X intersecting each X_i, (i=1..n). - Milan Janjic, Nov 18 2007
Equals row sums of triangle A152194. - Gary W. Adamson, Nov 28 2008
An elephant sequence, see A175655. For the central square 16 A[5] vectors, with decimal values between 19 and 400, lead to this sequence (without the first leading 1). For the corner squares these vectors lead to the companion sequence A045623. - Johannes W. Meijer, Aug 15 2010
a(n) is the total number of runs of 1 in the compositions of n+1. For example, a(3) = A045623(3) - A045623(2) = 12 - 5 = 7 runs of only 1 in the compositions of 4, enumerated "()" as follows: 3,(1); (1),3; 2,(1,1);(1),2,(1); (1,1),2; (1,1,1,1). More generally, the total number of runs of only part k in the compositions of n+k is A045623(n) - A045623(n-k). - Gregory L. Simay, May 02 2017
This is essentially the p-INVERT of (1,1,1,1,1,...) for p(S) = 1 - S - S^2 + S^3; see A291000. - Clark Kimberling, Aug 24 2017

Examples

			G.f. = 1 + x + 3*x^2 + 7*x^3 + 16*x^4 + 36*x^5 + 80*x^6 + ... - _Michael Somos_, Mar 26 2022
		

Crossrefs

Programs

Formula

a(n) = Sum_{k=0..n-2} (k+3)*binomial(n-2,k) for n >= 2. - N. J. A. Sloane, Jan 30 2008
a(n) = (n+4)*2^(n-3), n >= 2, with a(0) = a(1) = 1.
G.f.: (1-x)^3/(1-2*x)^2.
Equals binomial transform of A027656.
Starting 1, 3, 7, 16, ... this is ((n+5)*2^n - 0^n)/4, the binomial transform of (1, 2, 2, 3, 3, ...). - Paul Barry, May 20 2003
From Paul Barry, Nov 29 2004: (Start)
a(n) = ((n+4)*2^(n-1) + 3*C(0, n) - C(1, n))/4;
a(n) = Sum_{k=0..floor(n/2)} C(n, 2*k)*(k+1). (End)
a(n) = A045623(n-1) + 2^(n-2) = A034007(n+1) - 2^(n-2) for n>=2. - Philippe Deléham, Apr 20 2009
G.f.: 1 + Q(0)*x/(1-x)^2, where Q(k)= 1 + (k+1)*x/(1 - x - x*(1-x)/(x + (k+1)*(1-x)/Q(k+1))); (continued fraction). - Sergei N. Gladkovskii, Apr 25 2013
a(n) = Sum_{k=0..n} (k+1)*C(n-2,n-k). Peter Luschny, Apr 20 2015
From Amiram Eldar, Jan 13 2021: (Start)
Sum_{n>=0} 1/a(n) = 128*log(2) - 1292/15.
Sum_{n>=0} (-1)^n/a(n) = 782/15 - 128*log(3/2). (End)
E.g.f.: (2 - x + exp(2*x)*(2 + x))/4. - Stefano Spezia, Mar 26 2022

A062111 Upper-right triangle resulting from binomial transform calculation for nonnegative integers.

Original entry on oeis.org

0, 1, 1, 4, 3, 2, 12, 8, 5, 3, 32, 20, 12, 7, 4, 80, 48, 28, 16, 9, 5, 192, 112, 64, 36, 20, 11, 6, 448, 256, 144, 80, 44, 24, 13, 7, 1024, 576, 320, 176, 96, 52, 28, 15, 8, 2304, 1280, 704, 384, 208, 112, 60, 32, 17, 9, 5120, 2816, 1536, 832, 448, 240, 128, 68, 36, 19, 10
Offset: 0

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Author

Henry Bottomley, May 30 2001

Keywords

Comments

From Philippe Deléham, Apr 15 2007: (Start)
This triangle can be found in the Laisant reference in the following form:
.......................5...11..
...................4...9...20..
...............3...7..16...36..
...........2...5..12..28.......
.......1...3...8..20..48.......
...0...1...4..12..32..80....... (End)
Triangle A152920 reversed. - Philippe Deléham, Apr 21 2009

Examples

			As a lower triangle (T(n, k)):
    0;
    1,   1;
    4,   3,   2;
   12,   8,   5,  3;
   32,  20,  12,  7,  4;
   80,  48,  28, 16,  9,  5;
  192, 112,  64, 36, 20, 11,  6;
  448, 256, 144, 80, 44, 24, 13, 7;
		

Crossrefs

Rows include (essentially) A001787, A001792, A034007, A045623, A045891.
Diagonals include (essentially) A001477, A005408, A008586, A008598, A017113.
Column sums are A058877.

Programs

  • Magma
    [2^(n-k-1)*(n+k): k in [0..n], n in [0..12]]; // G. C. Greubel, Sep 28 2022
    
  • Mathematica
    Table[2^(n-k-1)*(n+k), {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Sep 28 2022 *)
  • SageMath
    def A062111(n,k): return 2^(n-k-1)*(n+k)
    flatten([[A062111(n,k) for k in range(n+1)] for n in range(12)]) # G. C. Greubel, Sep 28 2022

Formula

A(n, k) = A(n, k-1) + A(n+1, k) if k > n with A(n, n) = n.
A(n, k) = (k+n)*2^(k-n-1) if k >= n.
T(2*n, n) = 3*n*2^(n-1) = 3*A001787(n). - Philippe Deléham, Apr 21 2009
From G. C. Greubel, Sep 28 2022: (Start)
T(n, k) = 2^(n-k-1)*(n+k) for 0 <= k <= n, n >= 0.
T(m*n, n) = 2^((m-1)*n-1)*(m+1)*A001477(n), m >= 1.
T(2*n-1, n-1) = A130129(n-1).
T(2*n+1, n-1) = 12*A001787(n).
Sum_{k=0..n} T(n, k) = A058877(n+1).
Sum_{k=0..n} (-1)^k*T(n, k) = 3*A073371(n-2), n >= 2.
T(n, k) = A152920(n, n-k). (End)

A152920 Triangle read by rows: triangle A062111 reversed.

Original entry on oeis.org

0, 1, 1, 2, 3, 4, 3, 5, 8, 12, 4, 7, 12, 20, 32, 5, 9, 16, 28, 48, 80, 6, 11, 20, 36, 64, 112, 192, 7, 13, 24, 44, 80, 144, 256, 448, 8, 15, 28, 52, 96, 176, 320, 576, 1024, 9, 17, 32, 60, 112, 208, 384, 704, 1280, 2304, 10, 19, 36, 68, 128, 240, 448, 832, 1536, 2816, 5120
Offset: 0

Views

Author

Paul Curtz, Dec 15 2008

Keywords

Examples

			Triangle starts:
  0;
  1,  1;
  2,  3,  4;
  3,  5,  8, 12;
  4,  7, 12, 20, 32;
  ...
		

Crossrefs

Programs

  • Magma
    [2^k*(n-k/2): k in [0..n], n in [0..12]]; // G. C. Greubel, Sep 27 2022
    
  • Maple
    A062111 := proc(n,k) (k+n)*2^(k-n-1) ; end: A152920 := proc(n,k) A062111(n-k,n) ; end: for n from 0 to 15 do for k from 0 to n do printf("%d,",A152920(n,k)) ; od: od: # R. J. Mathar, Jan 22 2009
    # second Maple program:
    T:= proc(n, k) option remember;
         `if`(k=0, n, T(n, k-1)+T(n-1, k-1))
        end:
    seq(seq(T(n, k), k=0..n), n=0..12);  # Alois P. Heinz, Sep 12 2022
  • Mathematica
    t[0, k_]:= k; t[n_, k_]:= t[n, k]= t[n-1, k] + t[n-1, k+1];
    Table[t[n-k, k], {n,0,10}, {k,n,0,-1}]//Flatten (* Jean-François Alcover, Sep 11 2016 *)
  • SageMath
    flatten([[2^(k-1)*(2*n-k) for k in range(n+1)] for n in range(12)]) # G. C. Greubel, Sep 27 2022

Formula

Row sums: (2^n-1)(n+1) = A058877(n). - R. J. Mathar, Jan 22 2009
T(2n, n) = 3*n*2^(n-1) = 3*A001787(n). - Philippe Deléham, Apr 20 2009
From Werner Schulte, Jul 31 2020: (Start)
T(n, k) = (2*n-k) * 2^(k-1) for 0 <= k <= n.
G.f.: Sum_{n>=0, k=0..n} T(n,k) * x^k * t^n = t*(1+x-3*x*t) / ((1-t)^2 * (1-2*x*t)^2).
Sum_{k=0..n} (-1)^k * binomial(n,k) * T(n,k) = 0 for n >= 0.
Sum_{k=0..n} binomial(n,k) * T(n,k) = 2*n * 3^(n-1) for n >= 0.
Define the array B(n,p) = (Sum_{k=0..n} binomial(p+k,p) * T(n,k))/(n+p+1) for n >= 0 and p >= 0. Then see the comment of Robert Coquereaux (2014) at A193844. Conjecture: B(n+1,p) = A(n,p). (End)
T(n, k) = T(n, k-1) + T(n-1, k-1) for k>=1, T(n,0) = n. - Alois P. Heinz, Sep 12 2022
From G. C. Greubel, Sep 27 2022: (Start)
T(n, n-1) = A001792(n).
T(2*n-1, n-1) = A053220(n).
T(2*n+1, n-1) = 3*A001792(n).
T(m*n, n) = (2*m-1)*A001787(n), for m >= 1. (End)

Extensions

Edited by N. J. A. Sloane, Dec 19 2008
More terms from R. J. Mathar, Jan 22 2009

A091613 Triangle: T(n,k) = number of compositions (ordered partitions) of n such that some part is repeated consecutively k times and no part is repeated consecutively more than k times.

Original entry on oeis.org

1, 1, 1, 3, 0, 1, 4, 3, 0, 1, 7, 6, 2, 0, 1, 14, 10, 5, 2, 0, 1, 23, 23, 11, 4, 2, 0, 1, 39, 50, 22, 10, 4, 2, 0, 1, 71, 99, 48, 22, 9, 4, 2, 0, 1, 124, 200, 105, 46, 21, 9, 4, 2, 0, 1, 214, 404, 223, 101, 46, 20, 9, 4, 2, 0, 1, 378, 805, 468, 218, 98, 45, 20, 9, 4, 2, 0, 1, 661, 1599, 979, 466, 213, 98, 44, 20, 9, 4, 2, 0, 1
Offset: 1

Views

Author

Christian G. Bower, Jan 23 2004

Keywords

Comments

Cf. A232294 - A128695 = column 3. - Geoffrey Critzer, Mar 24 2014

Examples

			Triangle starts:
    1;
    1,   1;
    3,   0,   1;
    4,   3,   0,  1;
    7,   6,   2,  0,  1;
   14,  10,   5,  2,  0, 1;
   23,  23,  11,  4,  2, 0, 1;
   39,  50,  22, 10,  4, 2, 0, 1;
   71,  99,  48, 22,  9, 4, 2, 0, 1;
  124, 200, 105, 46, 21, 9, 4, 2, 0, 1;
  ...
In the partition 3+3+2+2+2+1+3+3+1, 2 is repeated consecutively 3 times, no part is repeated consecutively more than 3 times. (3 appears 4 times nonconsecutively.)
		

Crossrefs

Row sums: A000079(n-1) (2^(n-1)).
Inverse: A091614.
Square: A091615.
Convergent of columns: A034007.

Programs

  • Maple
    b:= proc(n, l, k) option remember; `if`(n=0, 1, add(`if`(
          i=l, 0, add(b(n-i*j, i, k), j=1..min(k, n/i))), i=1..n))
        end:
    T:= (n, k)-> b(n, 0, k)-b(n, 0, k-1):
    seq(seq(T(n, k), k=1..n), n=1..14);  # Alois P. Heinz, Feb 08 2017
  • Mathematica
    nn=15;Table[Take[Drop[Transpose[Map[PadRight[#,nn+1]&,Table[ CoefficientList[Series[1/(1-Sum[Sum[x^(j i),{i,1,k}]/Sum[x^(j i),{i,0,k}],{j,1,nn}])-1/(1-Sum[Sum[x^(j i),{i,1,k-1}]/Sum[x^(j i),{i,0,k-1}],{j,1,nn}]),{x,0,nn}],x],{k,1,nn}]]],1][[n]],n],{n,1,nn}]//Grid
    (* or *)
    Needs["Combinatorica`"];Table[Distribution[Map[Max,Map[Length,Map[Split, Level[Map[Permutations,IntegerPartitions[n,n]],{2}]],{2}]],Range[1,n]],{n,1,15}]//Grid (* Geoffrey Critzer, Mar 24 2014 *)
    b[n_, l_, k_] := b[n, l, k] = If[n == 0, 1, Sum[If[i == l, 0,
         Sum[b[n - i*j, i, k], {j, 1, Min[k, n/i]}]], {i, 1, n}]];
    T[n_, k_] := b[n, 0, k] - b[n, 0, k - 1];
    Table[T[n, k], {n, 1, 14}, {k, 1, n}] // Flatten (* Jean-François Alcover, Jun 04 2021, after Alois P. Heinz *)

Formula

G.f. for column k: 1/(1 - Sum_{i>=1} (x^i + x^(2*i) + ... + x^(k*i))/( 1 + x^i + x^(2*i) + ... + x^(k*i)) ) - 1/(1 - Sum_{i>=1} (x^i + x^(2*i) + ... + x^((k-1)*i))/( 1 + x^i + x^(2*i) + ... + x^((k-1)*i))). - Geoffrey Critzer, Mar 24 2014

A168230 a(n) = n + 2 - a(n-1) for n>1; a(1) = 0.

Original entry on oeis.org

0, 4, 1, 5, 2, 6, 3, 7, 4, 8, 5, 9, 6, 10, 7, 11, 8, 12, 9, 13, 10, 14, 11, 15, 12, 16, 13, 17, 14, 18, 15, 19, 16, 20, 17, 21, 18, 22, 19, 23, 20, 24, 21, 25, 22, 26, 23, 27, 24, 28, 25, 29, 26, 30, 27, 31, 28, 32, 29, 33, 30, 34, 31, 35, 32, 36, 33, 37, 34, 38, 35, 39, 36, 40, 37
Offset: 1

Views

Author

Vincenzo Librandi, Nov 21 2009

Keywords

Comments

Interleaving of A001477 and A000027 without first three terms.
Binomial transform of 0, 4 followed by a signed version of A005009.
Inverse binomial transform of A034007 without first and third term.

Examples

			a(2) = 2+2-a(1) = 4-0 = 4; a(3) = 3+2-a(2) = 5-4 = 1.
		

Crossrefs

Cf. A001477 (nonnegative integers), A000027 (positive integers), A168309 (repeat 4,-3), A005009 (7*2^n), A034007 (first differences of A045891).

Programs

  • Magma
    [ n eq 1 select 0 else -Self(n-1)+n+2: n in [1..75] ];
    
  • Mathematica
    a=3; Table[a=n-a, {n, 3, 200}] (* Vladimir Joseph Stephan Orlovsky, Nov 22 2009 *)
    CoefficientList[Series[x (4 - 3 x) / ((1 + x) (1 - x)^2),{x, 0, 100}], x] (* Vincenzo Librandi, Sep 16 2013 *)
    LinearRecurrence[{1,1,-1}, {0, 4, 1}, 50] (* G. C. Greubel, Jul 16 2016 *)
    nxt[{n_,a_}]:={n+1,n+3-a}; NestList[nxt,{1,0},80][[All,2]] (* Harvey P. Dale, May 28 2021 *)
  • PARI
    Vec(x^2*(4-3*x)/((1+x)*(1-x)^2) + O(x^100)) \\ Colin Barker, Nov 08 2014

Formula

G.f.: x^2*(4 - 3*x)/((1+x)*(1-x)^2).
a(n) = (7*(-1)^n + 2*n + 5)/4.
a(n) = a(n-2) + 1 for n>2; a(1)=0, a(2)=4.
a(n+1) - a(n) = A168309(n).
a(n) = a(n-1) + a(n-2) - a(n-3). - Colin Barker, Nov 08 2014
E.g.f.: (1/4)*(7 - 12*exp(x) + (5 + 2*x)*exp(2*x))*exp(-x). - G. C. Greubel, Jul 16 2016
Sum_{n>=2} (-1)^(n+1)/a(n) = 11/6. - Amiram Eldar, Feb 23 2023

Extensions

Edited, three comments, four formulas, MAGMA program added by Klaus Brockhaus, Nov 22 2009

A159694 a(n) = 2*a(n-1) + 2^(n-1), for n > 0, with a(0)=6.

Original entry on oeis.org

6, 13, 28, 60, 128, 272, 576, 1216, 2560, 5376, 11264, 23552, 49152, 102400, 212992, 442368, 917504, 1900544, 3932160, 8126464, 16777216, 34603008, 71303168, 146800640, 301989888, 620756992, 1275068416, 2617245696, 5368709120
Offset: 0

Views

Author

Philippe Deléham, Apr 20 2009

Keywords

Comments

Diagonal of triangles A062111, A152920.

Examples

			a(0) = 6,
a(1) = 2* 6 + 1 =  13,
a(2) = 2*13 + 2 =  28,
a(3) = 2*28 + 4 =  60,
a(4) = 2*60 + 8 = 128, ...
		

Crossrefs

Seventh row of triangle A062111. - Klaus Brockhaus, Sep 27 2009

Programs

  • Magma
    [(12+n)*2^(n-1): n in [0..30]]; // G. C. Greubel, Sep 27 2022
    
  • Mathematica
    Table[(6 + n/2)*2^n, {n, 0, 30}] (* Amiram Eldar, Jan 19 2021 *)
  • SageMath
    [(12+n)*2^(n-1) for n in range(30)] # G. C. Greubel, Sep 27 2022

Formula

a(n) = Sum_{k=0..n} (k+6)*binomial(n,k).
From Klaus Brockhaus, Sep 27 2009: (Start)
a(n) = (6 + n/2)*2^n.
G.f.: (6 - 11*x)/(1-2*x)^2. (End)
From Amiram Eldar, Jan 19 2021: (Start)
Sum_{n>=0} 1/a(n) = 8192*log(2) - 3934820/693.
Sum_{n>=0} (-1)^n/a(n) = 11509636/3465 - 8192*log(3/2). (End)
E.g.f.: (6 + x)*exp(2*x). - G. C. Greubel, Sep 27 2022

A188553 T(n,k) = Number of n X k binary arrays without the pattern 0 1 diagonally, vertically, antidiagonally or horizontally.

Original entry on oeis.org

2, 3, 3, 4, 5, 4, 5, 8, 7, 5, 6, 12, 12, 9, 6, 7, 17, 20, 16, 11, 7, 8, 23, 32, 28, 20, 13, 8, 9, 30, 49, 48, 36, 24, 15, 9, 10, 38, 72, 80, 64, 44, 28, 17, 10, 11, 47, 102, 129, 112, 80, 52, 32, 19, 11, 12, 57, 140, 201, 192, 144, 96, 60, 36, 21, 12, 13, 68, 187, 303, 321, 256, 176
Offset: 1

Views

Author

R. H. Hardin, Apr 04 2011

Keywords

Comments

From Miquel A. Fiol, Feb 06 2024: (Start)
Also, T(n,k) is the number of words of length k, x(1)x(2)...x(k), on the alphabet {0,1,...,n}, such that, for i=2,...,k, x(i)=either x(i-1) or x(i)=x(i-1)-1.
For the bijection between arrays and sequences, notice that the i-th column consists of 1's and then 0's, and there are x(i)=0 to n of 1's.
Such a bijection implies that all the empirical/conjectured formulas in A188554, A188555, A188556, A188557, A188558, and A188559 become correct.
(End)

Examples

			Table starts
..2..3..4..5...6...7...8...9...10...11...12....13....14....15....16.....17
..3..5..8.12..17..23..30..38...47...57...68....80....93...107...122....138
..4..7.12.20..32..49..72.102..140..187..244...312...392...485...592....714
..5..9.16.28..48..80.129.201..303..443..630...874..1186..1578..2063...2655
..6.11.20.36..64.112.192.321..522..825.1268..1898..2772..3958..5536...7599
..7.13.24.44..80.144.256.448..769.1291.2116..3384..5282..8054.12012..17548
..8.15.28.52..96.176.320.576.1024.1793.3084..5200..8584.13866.21920..33932
..9.17.32.60.112.208.384.704.1280.2304.4097..7181.12381.20965.34831..56751
.10.19.36.68.128.240.448.832.1536.2816.5120..9217.16398.28779.49744..84575
.11.21.40.76.144.272.512.960.1792.3328.6144.11264.20481.36879.65658.115402
Some solutions for 5 X 3:
  1 1 1   1 0 0   0 0 0   1 1 1   1 1 1   1 1 1   1 1 1
  1 1 1   0 0 0   0 0 0   1 1 1   1 1 1   1 1 1   1 1 1
  1 1 1   0 0 0   0 0 0   1 1 1   1 0 0   1 1 0   1 1 1
  1 1 1   0 0 0   0 0 0   1 1 0   0 0 0   1 0 0   1 1 1
  1 1 1   0 0 0   0 0 0   1 0 0   0 0 0   0 0 0   1 1 0
Some solutions for T(5,3): By taking the sums of the columns in the above arrays we get 555, 100, 000, 543, 322, 432, 554. - _Miquel A. Fiol_, Feb 04 2024
		

Crossrefs

Diagonal is A045623.
Column 4 is A086570.
Upper diagonals T(n,n+i) for i=1..8 give: A001792, A001787(n+1), A000337(n+1), A045618, A045889, A034009, A055250, A055251.
Lower diagonals T(n+i,n) for i=1..7 give: A045891(n+1), A034007(n+2), A111297(n+1), A159694(n-1), A159695(n-1), A159696(n-1), A159697(n-1).
Antidiagonal sums give A065220(n+5).

Programs

  • Maple
    T:= (n,k)-> `if`(k<=n+1, (2*n+3-k)*2^(k-2), (n+1-k)*binomial(k-1, n) * add(binomial(n, j-1)/(k-j)*T(n, j)*(-1)^(n-j), j=1..n+1)): seq(seq(T(n, 1+d-n), n=1..d), d=1..15); #Alois P. Heinz in the Sequence Fans Mailing List, Apr 04 2011 [We do not permit programs based on conjectures, but this program is now justified by Fiol's comment. - N. J. A. Sloane, Mar 09 2024]

Formula

Empirical: T(n,k) = (n+1)*2^(k-1) + (1-k)*2^(k-2) for k < n+3, and then the entire row n is a polynomial of degree n in k.
From Miquel A. Fiol, Feb 06 2024: (Start)
The above empirical formula is correct.
It can be proved that T(n,k) satisfies the recurrence
T(n,k) = Sum_{r=1..n+1} (-1)^(r+1)*binomial(n+1,r)*T(n,k-r)
with initial values
T(n,k) = Sum_{r=0..k-1} (n+1-r)*binomial(k-1,r) for k = 1..n+1. (End)

A159695 a(0)=7, a(n) = 2*a(n-1) + 2^(n-1) for n > 0.

Original entry on oeis.org

7, 15, 32, 68, 144, 304, 640, 1344, 2816, 5888, 12288, 25600, 53248, 110592, 229376, 475136, 983040, 2031616, 4194304, 8650752, 17825792, 36700160, 75497472, 155189248, 318767104, 654311424, 1342177280, 2751463424, 5637144576
Offset: 0

Views

Author

Philippe Deléham, Apr 20 2009

Keywords

Comments

Diagonal of triangles A062111, A152920.

Examples

			a(0)=7, a(1) = 2*7 + 1 = 15, a(2) = 2*15 + 2 = 32, a(3) = 2*32 + 4 = 68, a(4) = 2*68 + 8 = 144, ...
		

Crossrefs

Programs

  • Magma
    [(14+n)*2^(n-1): n in [0..30]]; // G. C. Greubel, Jun 02 2018
  • Mathematica
    LinearRecurrence[{4,-4}, {7,15}, 30] (* or *) Table[(14+n)*2^(n-1), {n, 0, 30}] (* G. C. Greubel, Jun 02 2018 *)
    nxt[{n_,a_}]:={n+1,2a+2^n}; NestList[nxt,{0,7},30][[All,2]] (* Harvey P. Dale, Jan 01 2023 *)
  • PARI
    for(n=0, 30, print1((14+n)*2^(n-1), ", ")) \\ G. C. Greubel, Jun 02 2018
    

Formula

a(n) = Sum_{k=0..n} (k+7)*binomial(n,k).
From R. J. Mathar, Apr 20 2009: (Start)
a(n) = (14+n)*2^(n-1).
a(n) = 4*a(n-1) - 4*a(n-2).
G.f.: (7-13*x)/(1-2x)^2. (End)
E.g.f.: (x+7)*exp(2*x). - G. C. Greubel, Jun 02 2018
From Amiram Eldar, Jan 19 2021: (Start)
Sum_{n>=0} 1/a(n) = 32768*log(2) - 204619418/9009.
Sum_{n>=0} (-1)^n/a(n) = 598484902/45045 - 32768*log(3/2). (End)

Extensions

More terms from R. J. Mathar, Apr 20 2009

A079028 a(0) = 1, a(n) = (n + 4)*4^(n-1) for n >= 1.

Original entry on oeis.org

1, 5, 24, 112, 512, 2304, 10240, 45056, 196608, 851968, 3670016, 15728640, 67108864, 285212672, 1207959552, 5100273664, 21474836480, 90194313216, 377957122048, 1580547964928, 6597069766656, 27487790694400, 114349209288704, 474989023199232, 1970324836974592, 8162774324609024
Offset: 0

Views

Author

Benoit Cloitre, Feb 01 2003

Keywords

Comments

a(n) = det(M(n)) where M(n) is the n X n matrix defined by m(i,i) = 5, m(i,j) = i/j.
Main diagonal of array defined by m(1,j) = j; m(i,1) = i and m(i,j) = m(i-1,j) + 3*m(i-1,j-1).
4th binomial transform of (1,1,0,0,0,0,...). - Paul Barry, Mar 07 2003
Number of independent vertex subsets of the graph obtained by attaching two pendant edges to each vertex of the complete graph K_n (see A235113). Example: a(1)=5; indeed, K_1 is the one vertex graph and after attaching two pendant vertices we obtain the path graph ABC; the independent vertex subsets are: empty, {A}, {B}, {C}, and {A,C}. - Emeric Deutsch, Jan 13 2014
Row sums of A235113.

Crossrefs

Programs

Formula

a(n) = 8*a(n-1)-16*a(n-2), a(0) = 1, a(1) = 5. - Paul Barry, Mar 07 2003
G.f.: (1 - 3*x)/(1 - 4*x)^2. - Philippe Deléham, Dec 11 2008
From Amiram Eldar, Jan 14 2021: (Start)
Sum_{n>=0} 1/a(n) = 1024*log(4/3) - 880/3.
Sum_{n>=0} (-1)^n/a(n) = 688/3 - 1024*log(5/4). (End)
E.g.f.: exp(4*x)*(1 + x). - Stefano Spezia, Mar 05 2023

Extensions

More terms from Stefano Spezia, Mar 05 2023

A159696 a(0)=8, a(n) = 2*a(n-1) + 2^(n-1) for n > 0.

Original entry on oeis.org

8, 17, 36, 76, 160, 336, 704, 1472, 3072, 6400, 13312, 27648, 57344, 118784, 245760, 507904, 1048576, 2162688, 4456448, 9175040, 18874368, 38797312, 79691776, 163577856, 335544320, 687865856, 1409286144, 2885681152, 5905580032
Offset: 0

Views

Author

Philippe Deléham, Apr 20 2009

Keywords

Comments

Diagonal of triangles A062111, A152920.

Examples

			a(0)=8, a(1) = 2*8 + 1 = 17, a(2) = 2*17 + 2 = 36, a(3) = 2*36 + 4 = 76, a(4) = 2*76 + 8 = 160, ...
		

Crossrefs

Programs

  • Magma
    [(16+n)*2^(n-1): n in [0..30]]; // G. C. Greubel, Jun 02 2018
  • Mathematica
    LinearRecurrence[{4,-4}, {8,17}, 30] (* or *) Table[(16+n)*2^(n-1), {n,0,30}] (* G. C. Greubel, Jun 02 2018 *)
  • PARI
    for(n=0, 30, print1((16+n)*2^(n-1), ", ")) \\ G. C. Greubel, Jun 02 2018
    

Formula

a(n) = Sum_{k=0..n} (k+8)*binomial(n,k).
From R. J. Mathar, Apr 20 2009: (Start)
a(n) = (16+n)*2^(n-1).
a(n) = 4*a(n-1) - 4*a(n-2).
G.f.: (8-15*x)/(1-2*x)^2. (End)
E.g.f.: (x+8)*exp(2*x). - G. C. Greubel, Jun 02 2018

Extensions

More terms from R. J. Mathar, Apr 20 2009
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