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 1-7 of 7 results.

A294212 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where column k is the expansion of e.g.f.: exp(Product_{j=1..n} 1/(1-x^j) - 1).

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 1, 3, 0, 1, 1, 5, 13, 0, 1, 1, 5, 25, 73, 0, 1, 1, 5, 31, 193, 501, 0, 1, 1, 5, 31, 241, 1601, 4051, 0, 1, 1, 5, 31, 265, 2261, 16741, 37633, 0, 1, 1, 5, 31, 265, 2501, 25501, 190345, 394353, 0, 1, 1, 5, 31, 265, 2621, 29461, 319915, 2509025
Offset: 0

Views

Author

Seiichi Manyama, Oct 25 2017

Keywords

Examples

			Square array B(j,k) begins:
   1,   1,    1,    1,    1, ...
   0,   1,    1,    1,    1, ...
   0,   1,    2,    2,    2, ...
   0,   1,    2,    3,    3, ...
   0,   1,    3,    4,    5, ...
   0,   1,    3,    5,    6, ...
Square array A(n,k) begins:
   1,   1,    1,    1,    1, ...
   0,   1,    1,    1,    1, ...
   0,   3,    5,    5,    5, ...
   0,  13,   25,   31,   31, ...
   0,  73,  193,  241,  265, ...
   0, 501, 1601, 2261, 2501, ...
		

Crossrefs

Columns k=0..5 give A000007, A000262, A294213, A294214, A294215, A294216.
Rows n=0 gives A000012.
Main diagonal gives A058892.

Formula

B(j,k) is the coefficient of Product_{i=1..k} 1/(1-x^i).
A(0,k) = 1 and A(n,k) = (n-1)! * Sum_{j=1..n} j*B(j,k)*A(n-j,k)/(n-j)! for n > 0.

A294250 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of e.g.f.: exp(Product_{j=1..n} (1+x^j) - 1).

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 3, 1, 0, 1, 1, 3, 13, 1, 0, 1, 1, 3, 19, 49, 1, 0, 1, 1, 3, 19, 97, 261, 1, 0, 1, 1, 3, 19, 121, 681, 1531, 1, 0, 1, 1, 3, 19, 121, 921, 5971, 9073, 1, 0, 1, 1, 3, 19, 121, 1041, 8491, 50443, 63393, 1, 0, 1, 1, 3, 19, 121, 1041
Offset: 0

Views

Author

Seiichi Manyama, Oct 26 2017

Keywords

Examples

			Square array A(n,k) begins:
   1, 1,   1,   1,   1, ...
   0, 1,   1,   1,   1, ...
   0, 1,   3,   3,   3, ...
   0, 1,  13,  19,  19, ...
   0, 1,  49,  97, 121, ...
   0, 1, 261, 681, 921, ...
		

Crossrefs

Columns k=0..5 give A000007, A000012, A118589, A294251, A294252, A294253.
Rows n=0 gives A000012.
Main diagonal gives A293840.

Formula

B(j,k) is the coefficient of Product_{i=1..k} (1+x^i).
A(0,k) = 1 and A(n,k) = (n-1)! * Sum_{j=1..min(A000217(k),n)} j*B(j,k)*A(n-j,k)/(n-j)! for n > 0.

A294260 E.g.f.: exp(Sum_{n>=1} A010815(n)*x^n).

Original entry on oeis.org

1, -1, -1, 5, 1, 79, -689, 2981, -7615, -172801, 3621151, -16469531, -240199871, 2722511375, 51840080111, -1987808959291, 12337235928961, 136594696115071, -1167414675803585, -56631124939839931, -1376838916423621759, 69766591820556094799
Offset: 0

Views

Author

Seiichi Manyama, Oct 26 2017

Keywords

Crossrefs

Main diagonal of A294254.
Cf. A293840.

Formula

a(0) = 1 and a(n) = (n-1)! * Sum_{k=1..n} k*A010815(k)*a(n-k)/(n-k)! for n > 0.

A294255 E.g.f.: exp((1-x)*(1-x^2) - 1).

Original entry on oeis.org

1, -1, -1, 11, -23, -101, 991, -1849, -24751, 220823, -174689, -10924541, 87639289, 105372851, -7496679553, 52397291519, 238887991201, -7313210597969, 41947208776639, 440627548672763, -9537975555701239, 39732691614159179, 916052993052974239
Offset: 0

Views

Author

Seiichi Manyama, Oct 26 2017

Keywords

Crossrefs

Column k=2 of A294254.

Programs

  • PARI
    N=66; x='x+O('x^N); Vec(serlaplace(exp((1-x)*(1-x^2)-1)))

A294256 E.g.f.: exp((1-x)*(1-x^2)*(1-x^3) - 1).

Original entry on oeis.org

1, -1, -1, 5, 25, -41, -1769, 7181, 74705, -236305, -7562609, -4169771, 1339186729, -2144219065, -174083994265, -370106105251, 35885107199521, 252732128552671, -10892824509622625, -56149731134394715, 2589936417283432121, 31565855231279227319
Offset: 0

Views

Author

Seiichi Manyama, Oct 26 2017

Keywords

Crossrefs

Column k=3 of A294254.

Programs

  • PARI
    N=66; x='x+O('x^N); Vec(serlaplace(exp((1-x)*(1-x^2)*(1-x^3)-1)))

A294257 E.g.f.: exp((1-x)*(1-x^2)*(1-x^3)*(1-x^4) - 1).

Original entry on oeis.org

1, -1, -1, 5, 1, 199, -1409, -4579, 25985, 23759, 13872511, -129511691, -1050605951, 4703204375, 33833371391, 6781977225869, -71864943455999, -926469142419809, -2738986440688385, 11032808190085349, 16738876153047304961, -146356319119622810521
Offset: 0

Views

Author

Seiichi Manyama, Oct 26 2017

Keywords

Crossrefs

Column k=4 of A294254.

Programs

  • PARI
    N=66; x='x+O('x^N); Vec(serlaplace(exp((1-x)*(1-x^2)*(1-x^3)*(1-x^4)-1)))

A294258 Expansion of e.g.f.: exp((1-x)*(1-x^2)*(1-x^3)*(1-x^4)*(1-x^5) - 1).

Original entry on oeis.org

1, -1, -1, 5, 1, 79, 31, -2059, -68095, 129599, 5586751, 36420229, -159700991, -6256012465, -94786800289, -3320395014091, 74018996229121, 1093450523140351, -4548151329265025, -222875601233847931, -7118941159301980159, -60758029090422335281
Offset: 0

Views

Author

Seiichi Manyama, Oct 26 2017

Keywords

Crossrefs

Column k=5 of A294254.

Programs

  • Mathematica
    With[{nn=30},CoefficientList[Series[Exp[Times@@(1-x^Range[5])-1],{x,0,nn}],x] Range[0,nn]!] (* Harvey P. Dale, Oct 29 2020 *)
  • PARI
    N=66; x='x+O('x^N); Vec(serlaplace(exp((1-x)*(1-x^2)*(1-x^3)*(1-x^4)*(1-x^5)-1)))

Extensions

Definition clarified by Harvey P. Dale, Oct 29 2020
Showing 1-7 of 7 results.