A349906 Number of factorizations of n into even factors > 1 (a(1) = 1 by convention).

1, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 7, 0, 1, 0, 3, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 7, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 3, 0, 1, 0, 11, 0, 1, 0, 2, 0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 7, 0, 1, 0, 3, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 12, 0, 1, 0, 3, 0, 1, 0, 4, 0

Offset

1,4

Links

Antti Karttunen, Table of n, a(n) for n = 1..20000

Prog

(PARI) A349906(n, m=n) = if(1==n, 1, my(s=0); fordiv(n, d, if((d>1)&&(d<=m)&&!(d%2), s += A349906(n/d, d))); (s));

Crossrefs

Cf. A001055, A340785 (even bisection), A349907.

Sequence in context: A007814 A265330 A272216 * A320439 A321252 A225345

Adjacent sequences: A349903 A349904 A349905 * A349907 A349908 A349909

Keyword

nonn

Author

Antti Karttunen, Dec 13 2021

Status

approved