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A221951
Number of subgroups of C_4 X C_n.
2
3, 8, 6, 15, 6, 16, 6, 22, 9, 16, 6, 30, 6, 16, 12, 29, 6, 24, 6, 30, 12, 16, 6, 44, 9, 16, 12, 30, 6, 32, 6, 36, 12, 16, 12, 45, 6, 16, 12, 44, 6, 32, 6, 30, 18, 16, 6, 58, 9, 24, 12, 30, 6, 32, 12, 44, 12, 16, 6, 60, 6, 16, 18, 43, 12, 32, 6, 30, 12, 32, 6, 66, 6, 16, 18, 30, 12, 32, 6, 58
OFFSET
1,1
LINKS
FORMULA
a(n) = Sum_{d|n} (1+gcd(2,d)+gcd(4,d)). - Antti Karttunen, Sep 30 2018
PROG
(PARI) A221951(n) = sumdiv(n, d, (1+gcd(2, d)+gcd(4, d))); \\ Antti Karttunen, Sep 30 2018
CROSSREFS
Row 4 of A216624.
Sequence in context: A155724 A289485 A304299 * A276574 A276584 A098737
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Feb 02 2013
STATUS
approved