OFFSET
0,5
COMMENTS
Zeros are ignored when computing GCD, and the empty set has GCD 0.
EXAMPLE
The a(2) = 1 through a(12) = 15 partitions (A = 10, B = 11, C = 12):
(2) (3) (4) (5) (6) (7) (8) (9) (A) (B) (C)
(22) (33) (52) (44) (63) (55) (83) (66)
(42) (62) (72) (64) (92) (84)
(222) (422) (333) (73) (722) (93)
(2222) (522) (82) (5222) (A2)
(442) (444)
(622) (552)
(4222) (633)
(22222) (642)
(822)
(3333)
(4422)
(6222)
(42222)
(222222)
MATHEMATICA
Table[Length[Select[IntegerPartitions[n], GCD@@Differences[#]!=GCD@@(#-1)&]], {n, 0, 30}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Oct 07 2019
STATUS
approved