OFFSET
0,4
FORMULA
G.f.: 1/(1 - x - Sum_{k>=2} x^prime(k)).
MAPLE
a:= proc(n) option remember; `if`(n=0, 1, a(n-1)+
add(`if`(isprime(j), a(n-j), 0), j=3..n))
end:
seq(a(n), n=0..42); # Alois P. Heinz, Aug 12 2019
MATHEMATICA
nmax = 42; CoefficientList[Series[1/(1 - x - Sum[x^Prime[k], {k, 2, nmax}]), {x, 0, nmax}], x]
a[0] = 1; a[n_] := a[n] = Sum[Boole[PrimeOmega[k] < 2 && OddQ[k]] a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 42}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Aug 12 2019
STATUS
approved