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 1-4 of 4 results.

A294605 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of Product_{j>=1} (1-j*x^j)^(j^(k*j)) in powers of x.

Original entry on oeis.org

1, 1, -1, 1, -1, -2, 1, -1, -8, -1, 1, -1, -32, -73, -1, 1, -1, -128, -2155, -919, 5, 1, -1, -512, -58921, -259477, -13977, 1, 1, -1, -2048, -1593811, -67041751, -48496477, -253640, 13, 1, -1, -8192, -43044673, -17178144301, -152513231553, -13001163543, -5290184, 4
Offset: 0

Views

Author

Seiichi Manyama, Nov 04 2017

Keywords

Examples

			Square array begins:
    1,    1,       1,         1,            1, ...
   -1,   -1,      -1,        -1,           -1, ...
   -2,   -8,     -32,      -128,         -512, ...
   -1,  -73,   -2155,    -58921,     -1593811, ...
   -1, -919, -259477, -67041751, -17178144301, ...
		

Crossrefs

Columns k=0..2 give A022661, A294606, A294607.
Rows n=0..1 give A000012, (-1)*A000012.

Formula

A(0,k) = 1 and A(n,k) = -(1/n) * Sum_{j=1..n} (Sum_{d|j} d^(k*d+1+j/d)) * A(n-j,k) for n > 0.

A294950 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of Product_{j>=1} 1/(1-j^(k*j)*x^j)^j in powers of x.

Original entry on oeis.org

1, 1, 1, 1, 1, 3, 1, 1, 9, 6, 1, 1, 33, 90, 13, 1, 1, 129, 2220, 1162, 24, 1, 1, 513, 59178, 265132, 17435, 48, 1, 1, 2049, 1594836, 67180330, 49163241, 310193, 86, 1, 1, 8193, 43048770, 17181660628, 152662629227, 13121450895, 6286826, 160
Offset: 0

Views

Author

Seiichi Manyama, Nov 12 2017

Keywords

Examples

			Square array begins:
    1,     1,        1,            1,               1, ...
    1,     1,        1,            1,               1, ...
    3,     9,       33,          129,             513, ...
    6,    90,     2220,        59178,         1594836, ...
   13,  1162,   265132,     67180330,     17181660628, ...
   24, 17435, 49163241, 152662629227, 476855156157129, ...
		

Crossrefs

Columns k=0..2 give A000219, A294813, A294954.
Rows n=0+1, 2 give A000012, A087289.

Formula

A(0,k) = 1 and A(n,k) = (1/n) * Sum_{j=1..n} (Sum_{d|j} d^(2+k*j)) * A(n-j,k) for n > 0.

A294610 Expansion of Product_{k>=1} 1/(1 - k*x^k)^(k^k).

Original entry on oeis.org

1, 1, 9, 90, 1154, 17427, 309117, 6285102, 144603015, 3717580810, 105696353842, 3293810230381, 111651093529948, 4089889271054734, 160989247361249558, 6776381334102511286, 303712681809603918633, 14439887378431671417669
Offset: 0

Views

Author

Seiichi Manyama, Nov 04 2017

Keywords

Crossrefs

Column k=1 of A294609.

Programs

  • Mathematica
    nmax = 20; CoefficientList[Series[Product[1/(1 - k*x^k)^(k^k), {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Nov 05 2017 *)
  • PARI
    N=66; x='x+O('x^N); Vec(1/prod(k=1, N, (1-k*x^k)^k^k))

Formula

a(0) = 1 and a(n) = (1/n) * Sum_{k=1..n} A294608(k) * a(n-k) for n > 0.

A294611 Expansion of Product_{k>=1} 1/(1 - k*x^k)^(k^(2*k)).

Original entry on oeis.org

1, 1, 33, 2220, 264908, 49163017, 13120646934, 4762819155533, 2257121941722156, 1353302171994081060, 1001440370811165212942, 896481721940248699989226, 954894511643935287905899347, 1193519554843091905978411389666
Offset: 0

Views

Author

Seiichi Manyama, Nov 04 2017

Keywords

Crossrefs

Column k=2 of A294609.
Cf. A294607.

Programs

  • Mathematica
    nmax = 20; CoefficientList[Series[Product[1/(1 - k*x^k)^(k^(2*k)), {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Nov 05 2017 *)
  • PARI
    N=20; x='x+O('x^N); Vec(1/prod(k=1, N, (1-k*x^k)^k^(2*k)))

Formula

Convolution inverse of A294607.
Showing 1-4 of 4 results.