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 1-5 of 5 results.

A094951 a(n) = A081038(n) + A077616(n).

Original entry on oeis.org

6, 31, 144, 621, 2538, 9963, 37908, 140697, 511758, 1830519, 6456024, 22497669, 77590386, 265189059, 899198172, 3027619377, 10130328342, 33705582543, 111577100832, 367662044061, 1206427402746, 3943553157531, 12845313733284
Offset: 1

Views

Author

Gary W. Adamson, May 26 2004

Keywords

Comments

Performing the same operation but using the multiplier [1 0 0] yields [3^n 2*A027471(n+1) A077616(n)]. Example: M^4 * [1 0 0] = [81 216 324] where 324 = A077616(4) and 216/2 = 108 = A027471(5).

Examples

			a(3) = 144 = 81 + 63 = A081038(3) + A077616(3).
a(4) = 621 = 297 + 324 = A081038(4) + A077616(4).
a(4) = 621 since M^4 * [1 1 1] = [81 297 621] = [3^4 A081038(4), a(4)].
		

Crossrefs

Programs

  • GAP
    List([1..30], n-> 3^(n-2)*(9+7*n+2*n^2)); # G. C. Greubel, Jun 06 2019
  • Magma
    [3^(n-2)*(9+7*n+2*n^2): n in [1..30]]; // G. C. Greubel, Jun 06 2019
    
  • Mathematica
    a[n_] := (MatrixPower[{{3, 0, 0}, {2, 3, 0}, {1, 2, 3}}, n].{{1}, {1}, {1}})[[3, 1]]; Table[ a[n], {n, 23}] (* Robert G. Wilson v, Jun 05 2004 *)
    Table[3^(n-2)*(9+7*n+2*n^2), {n,1,30}] (* G. C. Greubel, Jun 06 2019 *)
  • PARI
    vector(30, n, 3^(n-2)*(9+7*n+2*n^2)) \\ G. C. Greubel, Jun 06 2019
    
  • Sage
    [3^(n-2)*(9+7*n+2*n^2) for n in (1..30)] # G. C. Greubel, Jun 06 2019
    

Formula

a(n) = A081038(n) + A077616(n).
Let M = the 3 X 3 matrix [3 0 0 / 2 3 0 / 1 2 3]; then M^n * [1 1 1] = [3^n A081038(n) a(n)], where a(n) - A081038(n) = A077616(n).
From Colin Barker, Nov 09 2012: (Start)
a(n) = 3^(n-2)*(9 + 7*n + 2*n^2).
a(n) = 9*a(n-1) - 27*a(n-2) + 27*a(n-3).
G.f.: x*(6 - 23*x + 27*x^2)/(1-3*x)^3. (End)
E.g.f.: -1 + (1 + 3*x + 2*x^2)*exp(3*x). - G. C. Greubel, Jun 06 2019

Extensions

Edited and extended by Robert G. Wilson v, Jun 05 2004

A014477 Expansion of (1 + 2*x)/(1 - 2*x)^3.

Original entry on oeis.org

1, 8, 36, 128, 400, 1152, 3136, 8192, 20736, 51200, 123904, 294912, 692224, 1605632, 3686400, 8388608, 18939904, 42467328, 94633984, 209715200, 462422016, 1015021568, 2218786816, 4831838208, 10485760000, 22682796032, 48922361856, 105226698752, 225754218496
Offset: 0

Views

Author

Keywords

Comments

The sequence 0,1,8,... has a(n) = n^2*2^(n-1) and is the binomial transform of the hexagonal numbers A000384 (with leading 0). - Paul Barry, Jun 09 2003
As 0,1,8,... this is n^2*2^(n-1), the binomial transform of the hexagonal numbers A000384 (include the leading 0). Partial sums are A036826. - Paul Barry, Jun 10 2003
Sequence gives total value of all possible sums of distinct odd integers with maximum term less than 2n+1. E.g., for a(3) we can have the sums 1, 3, 5, 1+3, 1+5, 3+5, 1+3+5, which sum to 1+3+5+4+6+8+9 = 36. - Jon Perry, Feb 06 2004
Number of edges on a partially truncated (n+1)-cube (column 2 of A271316).

Crossrefs

Programs

Formula

O.g.f.: (1 + 2*x)/(1 - 2*x)^3 (see the name).
a(n) = (n+1)^2*2^n = A007758(n+1)/2. - Henry Bottomley, Jun 13 2001
The binomial transform of 0, 1, 8, ... is A077616. - Paul Barry, Jul 24 2003
a(1)=1, a(n) = 2a(n-1) + (2n-1)*2^(n-1). - Jon Perry, Feb 06 2004
a(n) = sum of (n+1)-th row of the triangle in A118416. - Reinhard Zumkeller, Apr 27 2006
a(n) = Sum_{j=0..n} binomial(n,j)*n*j. - Zerinvary Lajos, Oct 19 2006
E.g.f.: exp(2*x)*(1 + 6*x + 8*x^2/2!). - Wolfdieter Lang, Jul 29 2017
Sum_{n>=0} 1/a(n) = Pi^2/6 - log(2)^2. - Daniel Suteu, Oct 31 2017
Sum_{n>=0} (-1)^n/a(n) = -2 * Li_2(-1/2) = -2 * A355234. - Amiram Eldar, Oct 01 2022

A084901 a(n) = 4^(n-2)*n*(5*n+3)/2.

Original entry on oeis.org

0, 1, 13, 108, 736, 4480, 25344, 136192, 704512, 3538944, 17367040, 83623936, 396361728, 1853882368, 8573157376, 39258685440, 178241142784, 803158884352, 3594887626752, 15994458210304, 70781061038080, 311711546474496
Offset: 0

Views

Author

Paul Barry, Jun 10 2003

Keywords

Comments

Binomial transform of A084900. Third binomial transform of heptagonal numbers A000566. Fourth binomial transform of (0,1,5,0,0,0,...).
Coefficients in the hypergeometric series identity 1 - 13*x/(x + 12) + 108*x*(x - 1)/((x + 12)*(x + 16)) - 736*x*(x - 1)*(x - 2)/((x + 12)*(x + 16)*(x + 20)) + ... = 0, valid in the half-plane Re(x) > 0. Cf. A276289 and A077616. - Peter Bala, May 30 2019

Crossrefs

Programs

  • GAP
    List([0..30], n-> 2^(2*n-5)*n*(5*n+3)); # G. C. Greubel, Jun 06 2019
  • Magma
    [2^(2*n-5)*n*(5*n+3): n in [0..30]]; // G. C. Greubel, Jun 06 2019
    
  • Mathematica
    Table[2^(2*n-5)*n*(5*n+3), {n,0,30}] (* G. C. Greubel, Jun 06 2019 *)
    LinearRecurrence[{12,-48,64},{0,1,13},30] (* or *) CoefficientList[ Series[-((x (1+x))/(-1+4 x)^3),{x,0,30}],x] (* Harvey P. Dale, Jul 14 2021 *)
  • PARI
    vector(30, n, n--; 2^(2*n-5)*n*(5*n+3)) \\ G. C. Greubel, Jun 06 2019
    
  • Sage
    [2^(2*n-5)*n*(5*n+3) for n in (0..30)] # G. C. Greubel, Jun 06 2019
    

Formula

G.f.: x*(1+x)/(1-4*x)^3.
E.g.f.: x*(2 + 5*x)*exp(4*x)/2. - G. C. Greubel, Jun 06 2019
a(n) = 12*a(n-1)-48*a(n-2)+64*a(n-3). - Wesley Ivan Hurt, May 28 2021

A276289 Expansion of x*(1 + x)/(1 - 2*x)^3.

Original entry on oeis.org

0, 1, 7, 30, 104, 320, 912, 2464, 6400, 16128, 39680, 95744, 227328, 532480, 1232896, 2826240, 6422528, 14483456, 32440320, 72220672, 159907840, 352321536, 772800512, 1688207360, 3674210304, 7969177600, 17230200832, 37144756224, 79859548160, 171261820928, 366414397440
Offset: 0

Views

Author

Ilya Gutkovskiy, Aug 27 2016

Keywords

Comments

Binomial transform of pentagonal numbers (A000326).
More generally, the binomial transform of k-gonal numbers is n*Hypergeometric2F1(k/(k-2),1-n;2/(k-2);-1), where Hypergeometric2F1(a,b;c;x) is the hypergeometric function.
Coefficients in the hypergeometric series identity 1 - 7*x/(x + 6) + 30*x*(x - 1)/((x + 6)*(x + 8)) - 104*x*(x - 1)*(x - 2)/((x + 6)*(x + 8)*(x + 10)) + ... = 0, valid in the half-plane Re(x) > 0. Cf. A077616 and A084901. - Peter Bala, May 30 2019

Crossrefs

Cf. A001793 (binomial transform of triangular numbers), A001788 (binomial transform of squares), A084899 (binomial transform of heptagonal numbers).

Programs

  • GAP
    List([0..40], n-> 2^(n-3)*n*(3*n+1)); # G. C. Greubel, Jun 02 2019
  • Magma
    [2^(n-3)*n*(3*n+1): n in [0..40]]; // G. C. Greubel, Jun 02 2019
    
  • Maple
    a:=series(x*(1+x)/(1-2*x)^3,x=0,31): seq(coeff(a,x,n),n=0..40); # Paolo P. Lava, Mar 27 2019
  • Mathematica
    LinearRecurrence[{6, -12, 8}, {0, 1, 7}, 40]
    Table[2^(n - 3) n (3 n + 1), {n, 0, 40}]
  • PARI
    concat(0, Vec(x*(1+x)/(1-2*x)^3 + O(x^40))) \\ Altug Alkan, Aug 27 2016
    
  • Sage
    [2^(n-3)*n*(3*n+1) for n in (0..40)] # G. C. Greubel, Jun 02 2019
    

Formula

O.g.f.: x*(1 + x)/(1 - 2*x)^3.
E.g.f.: x*(2 + 3*x)*exp(2*x)/2.
a(n) = 6*a(n-1) - 12*a(n-2) + 8*a(n-3).
a(n) = Sum_{k = 0..n} binomial(n,k)*k*(3*k - 1)/2.
a(n) = 2^(n-3)*n*(3*n + 1).
Sum_{n>=1} 1/a(n) = 8*(-3*2^(1/3)*Hypergeometric2F1(1/3,1/3;4/3;-1) + 3 + log(2)) = 1.1906948190529335181687...

A062189 a(n) = 2 * 3^(n-2)*n*(1+2*n).

Original entry on oeis.org

0, 2, 20, 126, 648, 2970, 12636, 51030, 198288, 747954, 2755620, 9959598, 35429400, 124357194, 431530092, 1482720390, 5050815264, 17075199330, 57338232372, 191385721566, 635369601960, 2099044209402, 6903833113980
Offset: 0

Views

Author

Henry Bottomley, Jun 13 2001

Keywords

Comments

Define a triangle with left (first) column T(n,0)=n^2 for n=0,1,2,3.. and the remaining terms T(r,c) = T(r-1,c-1) + 2*T(r,c-1). Then T(n,n) = a(n) on the diagonal. T(n,1) = A056105(n). - J. M. Bergot, Jan 26 2013

Programs

  • GAP
    List([0..30], n-> 2*3^(n-2)*n*(1+2*n)); # G. C. Greubel, Jun 06 2019
  • Magma
    [2*3^(n-2)*n*(1+2*n): n in [0..30]]; // G. C. Greubel, Jun 06 2019
    
  • Mathematica
    Table[2*3^(n-2)*n*(1+2*n), {n,0,30}] (* G. C. Greubel, Jun 06 2019 *)
    LinearRecurrence[{9,-27,27},{0,2,20},30] (* Harvey P. Dale, Jun 08 2022 *)
  • PARI
    { for (n=0, 200, write("b062189.txt", n, " ", n*(4*n + 2)*3^(n - 2)) ) } \\ Harry J. Smith, Aug 02 2009
    
  • Sage
    [2*3^(n-2)*n*(1+2*n) for n in (0..30)] # G. C. Greubel, Jun 06 2019
    

Formula

a(n) = A002943(n)*A000244(n-2). Binomial transform of A007758.
G.f.: 2*x*(1+x)/(1-3*x)^3. - Ralf Stephan, Mar 13 2003
a(n) = 2*A077616(n). - R. J. Mathar, Jan 29 2013
E.g.f.: 2*x*(1+2*x)*exp(3*x). - G. C. Greubel, Jun 06 2019
Showing 1-5 of 5 results.