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 1-3 of 3 results.

A321344 Expansion of 1/(1 - x) * Product_{k>=0} 1/(1 - x^(3^k))^(3^(k+1)).

Original entry on oeis.org

1, 4, 10, 29, 71, 146, 309, 615, 1119, 2068, 3709, 6289, 10793, 18206, 29513, 48201, 77757, 121668, 191257, 297847, 452761, 690524, 1045661, 1552697, 2310786, 3419082, 4976739, 7254407, 10522736, 15052376, 21552205, 30731101, 43297942, 61039239, 85741503, 119191245
Offset: 0

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Author

Seiichi Manyama, Nov 06 2018

Keywords

Comments

Also the coefficient of x^(3*n) in the expansion of Product_{k>=0} 1/(1 - x^(3^k))^(3^k).

Examples

			Product_{k>=0} 1/(1 - x^(3^k))^(3^k) = 1 + x + x^2 + 4*x^3 + 4*x^4 + 4*x^5 + 10*x^6 + 10*x^7 + 10*x^8 + 29*x^9 + 29*x^10 + 29*x^11 + ... .
		

Crossrefs

Programs

  • PARI
    seq(n)={Vec(1/((1 - x)*prod(k=0, logint(n,3), (1 - x^(3^k) + O(x*x^n))^(3^(k+1)))))} \\ Andrew Howroyd, Nov 06 2018

A321345 Expansion of 1/(1 - x) * Product_{k>=0} 1/(1 - x^(4^k))^(4^(k+1)).

Original entry on oeis.org

1, 5, 15, 35, 86, 206, 450, 890, 1751, 3411, 6401, 11405, 20076, 35036, 59876, 99156, 162345, 263821, 422871, 663691, 1031914, 1594610, 2440286, 3678886, 5504759, 8196659, 12117745, 17715581, 25744904, 37267624, 53652824, 76576760, 108763319, 153984019, 217058009
Offset: 0

Views

Author

Seiichi Manyama, Nov 06 2018

Keywords

Comments

Also the coefficient of x^(4*n) in the expansion of Product_{k>=0} 1/(1 - x^(4^k))^(4^k).

Examples

			Product_{k>=0} 1/(1 - x^(4^k))^(4^k) = 1 + x + x^2 + x^3 + 5*x^4 + 5*x^5 + 5*x^6 + 5*x^7 + 15*x^8 + 15*x^9 + 15*x^10 + 15*x^11 + 35*x^12 + 35*x^13 + 35*x^14 + 35*x^15 + ... .
		

Crossrefs

Programs

  • PARI
    seq(n)={Vec(1/((1 - x)*prod(k=0, logint(n,4), (1 - x^(4^k) + O(x*x^n))^(4^(k+1)))))} \\ Andrew Howroyd, Nov 06 2018

A321336 Expansion of Product_{k>=0} (1 - x^(2^k))^(2^(k+1)).

Original entry on oeis.org

1, -2, -3, 8, -6, 4, 26, -56, -7, 70, -51, 32, 120, -272, -200, 672, -182, -308, 1026, -1744, -660, 3064, -916, -1232, 2466, -3700, -3990, 11680, -1416, -8848, 13752, -18656, -8503, 35662, -14331, -7000, 27122, -47244, -29870, 106984, -25895, -55194, 140173, -225152
Offset: 0

Views

Author

Seiichi Manyama, Nov 05 2018

Keywords

Crossrefs

Formula

Equals the self-convolution of A321327.
G.f.: A(x) satisfies A(x) = ((1 - x) * A(x^2))^2, with A(0) = 1.
a(n) = A321327(2*n) for n >= 0.
Showing 1-3 of 3 results.