OFFSET
0,5
FORMULA
G.f.: 2*(2 - 1/ASM(x)) - ASM(x) where ASM(x) is the g.f. of A005130.
EXAMPLE
a(3) = 1 because the only ASM of size 3 indecomposable by direct and skew sums is
[0 1 0]
[1 -1 1]
[0 1 0]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ludovic Schwob, Jun 15 2023
STATUS
approved