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.

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A335666 a(n) is the sum, over all overpartitions of n, of the overlined parts.

Original entry on oeis.org

1, 3, 10, 21, 46, 90, 168, 295, 511, 850, 1382, 2198, 3430, 5260, 7960, 11861, 17468, 25445, 36670, 52346, 74092, 103986, 144840, 200322, 275191, 375662, 509816, 687960, 923442, 1233340, 1639312, 2168999, 2857460, 3748772, 4898652, 6377023, 8271294, 10690830, 13771912, 17683642
Offset: 1

Views

Author

Jeremy Lovejoy, Jun 17 2020

Keywords

Examples

			The 8 overpartitions of 8 are [3], [3'], [2,1], [2,1'], [2',1], [2',1'], [1,1,1], [1',1,1], and so a(3) = 10.
		

Crossrefs

Cf. A305101 (number of overlined parts).

Programs

  • PARI
    my(N=44, q='q+O('q^N)); Vec( prod(k=1,N, (1+q^k)/(1-q^k)) * sum(k=1,N, k*q^k/(1+q^k)) ) \\ Joerg Arndt, Jun 18 2020

Formula

G.f.: (Product_{k>=1} (1+q^k)/(1-q^k)) * Sum_{n>=1} n*q^n/(1+q^n).
a(n) = A235793(n) - A335651(n). - Omar E. Pol, Jun 17 2020

A359481 Irregular triangle read by rows in which T(n,k) is one half of the number of overpartitions of n having k distinct parts, n>=1, k>=1.

Original entry on oeis.org

1, 2, 2, 2, 3, 4, 2, 10, 4, 12, 4, 2, 22, 8, 4, 26, 20, 3, 34, 40, 4, 44, 60, 8, 2, 54, 100, 16, 6, 58, 148, 40, 2, 74, 208, 80, 4, 88, 268, 160, 4, 88, 388, 240, 16, 5, 110, 468, 416, 32, 2, 118, 616, 616, 80, 6, 136, 736, 936, 160, 2, 142, 940, 1296, 320, 6, 162, 1108, 1816, 576
Offset: 1

Views

Author

Omar E. Pol, Mar 31 2023

Keywords

Examples

			Triangle begins:
  1;
  2;
  2,  2;
  3,  4;
  2, 10;
  4, 12,   4;
  2, 22,   8;
  4, 26,  20;
  3, 34,  40;
  4, 44,  60,   8;
  2, 54, 100,  16;
  6, 58, 148,  40;
  2, 74, 208,  80;
  4, 88, 268, 160;
  4, 88, 388, 240, 16;
  ...
		

Crossrefs

Column 1 gives A000005.
Row n has length A003056(n).
Row sums give A014968, n >= 1.
The first element of column k is A000079(k-1).
The first element of column k is in row A000217(k).

Formula

T(n,k) = (1/2)*A235790(n,k).
T(n,k) = (2^(k-1))*A116608(n,k).
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