OFFSET
0,4
COMMENTS
Zeros are ignored when computing GCD, and the empty set has GCD 0.
EXAMPLE
The a(1) = 1 through a(8) = 17 partitions:
(1) (11) (21) (31) (32) (51) (43) (53)
(111) (211) (41) (321) (61) (71)
(1111) (221) (411) (322) (332)
(311) (2211) (331) (431)
(2111) (3111) (421) (521)
(11111) (21111) (511) (611)
(111111) (2221) (3221)
(3211) (3311)
(4111) (4211)
(22111) (5111)
(31111) (22211)
(211111) (32111)
(1111111) (41111)
(221111)
(311111)
(2111111)
(11111111)
MATHEMATICA
Table[Length[Select[IntegerPartitions[n], GCD@@Differences[#]==GCD@@(#-1)&]], {n, 0, 30}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Oct 07 2019
STATUS
approved