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A292350 Number of Lyndon words (aperiodic necklaces) with 6 beads of n colors. 2
0, 9, 116, 670, 2580, 7735, 19544, 43596, 88440, 166485, 295020, 497354, 804076, 1254435, 1897840, 2795480, 4022064, 5667681, 7839780, 10665270, 14292740, 18894799, 24670536, 31848100, 40687400, 51482925, 64566684, 80311266, 99133020, 121495355, 147912160 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
a(n) = (n^6 - n^3 - n^2 + n)/6.
From Colin Barker, Dec 08 2017: (Start)
G.f.: x^2*(9 + 53*x + 47*x^2 + 11*x^3) / (1 - x)^7.
a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>7.
(End)
PROG
(PARI) concat(0, Vec(x^2*(9 + 53*x + 47*x^2 + 11*x^3) / (1 - x)^7 + O(x^40))) \\ Colin Barker, Dec 08 2017
CROSSREFS
Row n=6 of A074650.
Sequence in context: A223499 A362774 A157233 * A188976 A180913 A341964
KEYWORD
nonn,easy
AUTHOR
Eric M. Schmidt, Dec 08 2017
STATUS
approved

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Last modified April 14 05:31 EDT 2024. Contains 371655 sequences. (Running on oeis4.)