OFFSET
0,8
COMMENTS
A partition of n is a weakly decreasing sequence of positive integers summing to n.
The alternating sum of a sequence (y_1,...,y_k) is Sum_i (-1)^(i-1) y_i.
EXAMPLE
The a(4) = 1 through a(13) = 9 partitions:
31 311 42 322 53 333 64 443 75 553
421 5111 432 5221 542 5331 652
531 6211 641 6222 751
51111 52211 6321 52222
62111 7311 53311
711111 62221
63211
73111
7111111
MATHEMATICA
ats[y_]:=Sum[(-1)^(i-1)*y[[i]], {i, Length[y]}];
Table[Length[Select[IntegerPartitions[n], Length[#]==ats[#]&]], {n, 0, 30}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Sep 30 2022
STATUS
approved