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.

A290217 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of g.f. Product_{i>0} 1/(1 + Sum_{j=1..k} j*x^(j*i)).

Original entry on oeis.org

1, 1, 0, 1, -1, 0, 1, -1, 0, 0, 1, -1, -2, -1, 0, 1, -1, -2, 3, 1, 0, 1, -1, -2, 0, -1, -1, 0, 1, -1, -2, 0, 5, -5, 1, 0, 1, -1, -2, 0, 1, 1, 9, -1, 0, 1, -1, -2, 0, 1, 9, -12, 3, 2, 0, 1, -1, -2, 0, 1, 4, -4, -3, -20, -2, 0, 1, -1, -2, 0, 1, 4, 6, -15, 31, 16, 2
Offset: 0

Views

Author

Seiichi Manyama, Oct 06 2017

Keywords

Examples

			Square array begins:
   1,  1,  1,  1,  1, ...
   0, -1, -1, -1, -1, ...
   0,  0, -2, -2, -2, ...
   0, -1,  3,  0,  0, ...
   0,  1, -1,  5,  1, ...
   0, -1, -5,  1,  9, ...
		

Crossrefs

Columns k=0..3 give A000007, A081362, A293287, A290395.
Rows n=0..1 give A000012, (-1)*A057427.
Main diagonal gives A258210.

A293377 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of g.f. Product_{i>0} (1 + Sum_{j=1..k} j*x^(j*i))^2.

Original entry on oeis.org

1, 1, 0, 1, 2, 0, 1, 2, 3, 0, 1, 2, 7, 6, 0, 1, 2, 7, 10, 9, 0, 1, 2, 7, 16, 25, 14, 0, 1, 2, 7, 16, 31, 38, 22, 0, 1, 2, 7, 16, 39, 62, 78, 32, 0, 1, 2, 7, 16, 39, 70, 117, 116, 46, 0, 1, 2, 7, 16, 39, 80, 149, 206, 206, 66, 0, 1, 2, 7, 16, 39, 80, 159, 262, 362
Offset: 0

Views

Author

Seiichi Manyama, Oct 07 2017

Keywords

Examples

			Square array begins:
   1,  1,  1,  1,  1, ...
   0,  2,  2,  2,  2, ...
   0,  3,  7,  7,  7, ...
   0,  6, 10, 16, 16, ...
   0,  9, 25, 31, 39, ...
   0, 14, 38, 62, 70, ...
		

Crossrefs

Columns k=0..1 give A000007, A022567.
Rows n=0 gives A000012.
Main diagonal gives A293378.
Product_{i>0} (1 + Sum_{j=1..k} j*x^(j*i))^m: A290217 (m=-1), A290216 (m=1), this sequence (m=2).

A290269 G.f.: Product_{m>0} (1 + x^m + 2*x^(2*m) + 3*x^(3*m)).

Original entry on oeis.org

1, 1, 3, 5, 6, 10, 18, 25, 34, 53, 66, 94, 136, 179, 236, 325, 416, 550, 714, 913, 1181, 1530, 1917, 2446, 3091, 3862, 4828, 6051, 7457, 9233, 11465, 14028, 17181, 21099, 25651, 31251, 37948, 45853, 55380, 66833, 80236, 96271, 115496, 137822, 164470, 196094, 232837
Offset: 0

Views

Author

Seiichi Manyama, Oct 06 2017

Keywords

Crossrefs

Column k=3 of A290216.

Programs

  • PARI
    m = 30; Vec(prod(k=1, m, 1 + x^k + 2*x^(2*k) + 3*x^(3*k)) + O(x^m)) \\ Michel Marcus, Oct 07 2017

A293461 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of g.f. Product_{i>0} (1 + Sum_{j=1..k} j*x^(j*(2*i-1))).

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 2, 1, 0, 1, 1, 2, 1, 1, 0, 1, 1, 2, 4, 1, 1, 0, 1, 1, 2, 4, 1, 3, 1, 0, 1, 1, 2, 4, 5, 3, 3, 1, 0, 1, 1, 2, 4, 5, 3, 6, 5, 2, 0, 1, 1, 2, 4, 5, 8, 6, 5, 6, 2, 0, 1, 1, 2, 4, 5, 8, 6, 9, 9, 4, 2, 0, 1, 1, 2, 4, 5, 8, 12, 9, 9, 13
Offset: 0

Views

Author

Seiichi Manyama, Oct 09 2017

Keywords

Examples

			Square array begins:
   1, 1, 1, 1, 1, ...
   0, 1, 1, 1, 1, ...
   0, 0, 2, 2, 2, ...
   0, 1, 1, 4, 4, ...
   0, 1, 1, 1, 5, ...
   0, 1, 3, 3, 3, ...
		

Crossrefs

Columns k=0..3 give A000007, A000700, A293304, A293463.
Rows n=0..1 give A000012, A057427.
Main diagonal gives A102186.
Cf. A290216.

Programs

  • Mathematica
    max = 12; A[n_, k_] := SeriesCoefficient[Product[(x*(-(k*x^((2*i - 1)*(k + 1) + 1)) - x^((2*i - 1)*(k + 1) + 1) + k*x^((2*i - 1)*(k + 1) + 2*i) + x^(2*i)))/(x^(2*i) - x)^2 + 1, {i, 1, max}], {x, 0, n}]; Flatten[ Table[ A[n - k, k], {n, 0, max}, {k, n, 0, -1}]] (* Jean-François Alcover, Oct 10 2017 *)

A293386 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of g.f. Product_{i>0} 1/(1 + Sum_{j=1..k} j*x^(j*i))^2.

Original entry on oeis.org

1, 1, 0, 1, -2, 0, 1, -2, 1, 0, 1, -2, -3, -2, 0, 1, -2, -3, 10, 4, 0, 1, -2, -3, 4, -4, -4, 0, 1, -2, -3, 4, 14, -20, 5, 0, 1, -2, -3, 4, 6, -8, 41, -6, 0, 1, -2, -3, 4, 6, 16, -46, 2, 9, 0, 1, -2, -3, 4, 6, 6, -30, 14, -111, -12, 0, 1, -2, -3, 4, 6, 6, 0, -58
Offset: 0

Views

Author

Seiichi Manyama, Oct 07 2017

Keywords

Examples

			Square array begins:
   1,  1,   1,  1,  1, ...
   0, -2,  -2, -2, -2, ...
   0,  1,  -3, -3, -3, ...
   0, -2,  10,  4,  4, ...
   0,  4,  -4, 14,  6, ...
   0, -4, -20, -8, 16, ...
		

Crossrefs

Columns k=0..1 give A000007, A022597.
Rows n=0 gives A000012.
Main diagonal gives A252650.
Product_{i>0} (1 + Sum_{j=1..k} j*x^(j*i))^m: this sequence (m=-2), A290217 (m=-1), A290216 (m=1), A293377 (m=2).
Showing 1-5 of 5 results.