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A091605 Column 2 of triangle A091602. 2
1, 0, 2, 2, 3, 4, 7, 8, 12, 15, 21, 26, 35, 43, 57, 70, 89, 109, 138, 167, 208, 251, 309, 371, 452, 539, 652, 775, 929, 1099, 1311, 1543, 1829, 2146, 2529, 2957, 3469, 4040, 4721, 5481, 6377, 7381, 8559, 9875, 11412, 13133, 15128, 17364, 19945, 22833 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 2..1000

FORMULA

a(n) = A000726(n) - A000009(n).

EXAMPLE

a(7) counts these partitions:  511, 331, 322, 3211. - Clark Kimberling, Mar 10 2014

MATHEMATICA

d[n_] := Select[IntegerPartitions[n], Max[Length /@ Split@#] == 2 &];

t = Table[d[n], {n, 12}]  (* shows partitions *)

u = Table[Length[d[n]], {n, 2, 30}] (* counts partitions *)

(* Clark Kimberling, Mar 10 2014 *)

CROSSREFS

Sequence in context: A058670 A215367 A276526 * A145468 A125554 A345867

Adjacent sequences:  A091602 A091603 A091604 * A091606 A091607 A091608

KEYWORD

nonn

AUTHOR

Christian G. Bower, Jan 23 2004

STATUS

approved

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Last modified October 17 13:20 EDT 2021. Contains 348049 sequences. (Running on oeis4.)