

A274108


Number of partitions of n into parts with exactly two different sizes, the sizes being relatively prime.


3



0, 0, 1, 2, 5, 5, 11, 11, 16, 17, 27, 21, 37, 33, 38, 42, 59, 46, 71, 57, 70, 75, 97, 72, 104, 99, 109, 103, 141, 102, 157, 133, 148, 153, 166, 140, 207, 183, 192, 174, 241, 180, 259, 215, 223, 247, 295, 219, 300, 260, 292, 279, 353, 275, 336, 300, 346, 351
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OFFSET

1,4


LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..10000
N. Benyahia Tani, S. Bouroubi, O. Kihel, An effective approach for integer partitions using exactly two distinct sizes of parts, Bulletin du Laboratoire, 03 (2015) 18  27.


EXAMPLE

Explanation of a(3)a(6):
n=3: 21
n=4: 31, 211
n=5: 41, 32, 311, 221, 2111
n=6: 51, 411, 3111, 2211, 21111


CROSSREFS

Row sums of triangle in A274109.
Cf. A002133, A117955, A117956, A216665.
Sequence in context: A194119 A084721 A273041 * A138316 A183719 A239340
Adjacent sequences: A274105 A274106 A274107 * A274109 A274110 A274111


KEYWORD

nonn,look


AUTHOR

N. J. A. Sloane, Jun 17 2016


EXTENSIONS

More terms from Alois P. Heinz, Jun 23 2016


STATUS

approved



