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A007985 Co-growth function of a certain group. 1
2, 2, 6, 22, 58, 146, 414, 1206, 3410, 9634, 27670, 79926, 230666, 667058, 1936174, 5632662, 16408866, 47875650, 139908774, 409404630, 1199368026, 3517351890, 10325547582, 30339113718, 89217594738, 262561101282, 773248631222, 2278737199606 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
REFERENCES
Stephen P Humphries, "Cogrowth of groups and the Dedekind-Frobenius group determinant", Mathematical Proceeding of the Cambridge Philosophical Society volume 121 Part 2 pages 193-217 (1997).
LINKS
FORMULA
G.f. (x+1) * sqrt(1-x) / sqrt((1-3*x) * (3*x^2+1)) [from Humphries]. - Sean A. Irvine, Feb 26 2018
CROSSREFS
Sequence in context: A004077 A271217 A202743 * A097090 A085403 A112478
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms from Sean A. Irvine, Feb 26 2018
STATUS
approved

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Last modified June 15 10:19 EDT 2024. Contains 373407 sequences. (Running on oeis4.)