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.

A173303 Row sums of triangle A173302.

Original entry on oeis.org

1, 2, 3, 6, 9, 14, 21, 32, 45, 65, 90, 125, 170, 231, 307, 411, 539, 707, 917, 1188, 1522, 1950, 2475, 3137, 3949, 4962, 6195, 7725, 9579, 11856, 14610, 17971, 22012, 26919, 32798, 39892, 48367, 58541, 70647, 85123, 102291, 122724, 146891, 175545, 209322
Offset: 0

Views

Author

Gary W. Adamson, Feb 15 2010

Keywords

Comments

Each term is a sum of partition numbers.

Examples

			a(7) = 32 = (1 + 5 + 11 + 15), = p(0) + p(4) + p(6) + p(7).
		

Crossrefs

Row sums of A173302.

Programs

  • PARI
    a(n) = sum(k=0, logint(n+1, 2), numbpart(n + 1 - 2^k)) \\ Andrew Howroyd, Aug 10 2018

Formula

a(n) = Sum_{k >=0, 2^k <= n + 1} A000041(n + 1 - 2^k). - Andrew Howroyd, Aug 10 2018

Extensions

Terms a(21) and beyond from Andrew Howroyd, Aug 10 2018

A173304 Triangle generated from the array in A173302 (partition numbers starting new rows at n = 1, 3, 7, 15, ...).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 2, 3, 2, 4, 4, 3, 4, 6, 4, 7, 8, 6, 1, 8, 11, 9, 2, 12, 15, 12, 3, 14, 20, 17, 5, 21, 26, 23, 7, 24, 35, 31, 11, 34, 45, 41, 15, 41, 58, 55, 21, 1, 55, 75, 71, 29, 1, 66, 96, 93, 40, 2, 88, 121, 120, 53, 3, 105, 154, 154, 72, 5, 137, 193, 196, 94, 7
Offset: 0

Views

Author

Gary W. Adamson, Feb 15 2010

Keywords

Comments

Row sums = A000041, the partition numbers.

Examples

			The finite difference array starts:
  1, 1, 1, 1, 2, 2, 4, 4, 7,  8, 12, 14, 21, 24, ...; = A002865 (a variant)
        1, 1, 2, 3, 4, 6, 8, 11, 15, 20, 26, 35, ...; = A027336
           1, 1, 2, 3, 4, 6,  9, 12, 17, 23, 31, ...; = A017338
                       1, 1,  2,  3,  5,  7, 11, ...; = A027342
  ...
Last, columns of the array become rows of triangle A173304:
    1;
    1;
    1,   1;
    2,   2,   1;
    2,   3,   2;
    4,   4,   3;
    4,   6,   4,  1;
    7,   8,   6,  1;
    8,  11,   9,  2;
   12,  15,  12,  3;
   14,  20,  17,  5;
   21,  26,  23,  7;
   24,  35,  31, 11;
   34,  45,  41, 15;
   41,  58,  55, 21, 1;
   55,  75,  71, 29, 1;
   66,  96,  93, 40, 2;
   88, 121, 120, 53, 3;
  105, 154, 154, 72, 5;
  137, 193, 196, 94, 7;
  ...
		

Crossrefs

Formula

The generating array is in A173302.
1, 1, 2, 3, 5, 7, 11, 15, 22, 30, 42, 56, 77, 101, 135, 176, ...
1, 1, 2, 3, 5, 7, 11, 15, 22, 30, 42, 56, 77, 101, 135, ...
1, 1, 2, 3, 5, 7, 11, 15, 22, 30, 42, 56, 77, ...
1, 1, 2, 3, 5, 7, 11, 15, 22, ...
1, ...
...
Take finite differences from the bottom, creating a new array in which rows are A002865 (a slight variant), A027336, A027338, A027342, ...; i.e., the numbers of partitions of n that do not contain (1, 2, 4, 8, ...) as a part.

A173301 a(n) = A000041(2^n - 1).

Original entry on oeis.org

1, 1, 3, 15, 176, 6842, 1505499, 3913864295, 338854264248680, 4216199393504640098482, 59475094770587936660132803278445, 17618334934720173062514849536736413843694654543
Offset: 0

Views

Author

Gary W. Adamson, Feb 15 2010

Keywords

Comments

The partition numbers have an apparent fractal-like structure starting with every term in A173301.
Let A000041 = row 0, then under every (2^n - 1)-th term, begin a new row with the partition numbers; then take finite differences of each column from below.
The sum of finite difference terms will reproduce the partition numbers, with finite difference rows (starting from the top going down) = number of partitions of n that do not contain (1, 2, 3,...). (Cf. the array shown in A173302).

References

  • Refer to tables of the partition numbers.

Crossrefs

Programs

  • Mathematica
    Table[PartitionsP[2^n - 1], {n, 0 ,10}] (* Amiram Eldar, Feb 26 2020 *)

Formula

a(n) = A000041(2^n - 1), n = (0, 1, 2,...).
a(n) = A000041(A000225(n)). - Omar E. Pol, Oct 29 2013
Showing 1-3 of 3 results.