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A378278
Cogrowth sequence of the 20-element Frobenius group Frob20 = <S,T | S^5, T^4, (ST)^4>.
1
1, 0, 0, 0, 1, 1, 3, 7, 15, 27, 51, 99, 199, 403, 819, 1651, 3303, 6579, 13107, 26163, 52327, 104755, 209715, 419635, 839271, 1678131, 3355443, 6710067, 13420135, 26841907, 53687091, 107377459, 214754919, 429503283, 858993459, 1717973811, 3435947623
OFFSET
0,7
FORMULA
G.f.: (x^6+x^4+x^3-3*x^2+3*x-1) / ((2*x-1) * (x+1) * (x^2+1)/(2*x^2-2*x+1)).
CROSSREFS
Cf. A078789 (D10), A378254 (C10 X C2), A378276 (Dic20).
Sequence in context: A146742 A146425 A147595 * A147127 A146726 A146228
KEYWORD
nonn,easy
AUTHOR
Sean A. Irvine, Nov 21 2024
STATUS
approved