A169454 - OEIS

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A169454

Number of reduced words of length n in Coxeter group on 9 generators S_i with relations (S_i)^2 = (S_i S_j)^33 = I.

1, 9, 72, 576, 4608, 36864, 294912, 2359296, 18874368, 150994944, 1207959552, 9663676416, 77309411328, 618475290624, 4947802324992, 39582418599936, 316659348799488, 2533274790395904, 20266198323167232, 162129586585337856 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`0,2`
	COMMENTS	`The initial terms coincide with those of A003951, although the two sequences are eventually different.` `Computed with MAGMA using commands similar to those used to compute A154638.`
	LINKS	`Table of n, a(n) for n=0..19.` `Index entries for linear recurrences with constant coefficients, signature (7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, -28).`
	FORMULA	`G.f. (t^33 + 2t^32 + 2t^31 + 2t^30 + 2t^29 + 2t^28 + 2t^27 + 2t^26 +` `2t^25 + 2t^24 + 2t^23 + 2t^22 + 2t^21 + 2t^20 + 2t^19 + 2t^18 +` `2t^17 + 2t^16 + 2t^15 + 2t^14 + 2t^13 + 2t^12 + 2t^11 + 2t^10 +` `2t^9 + 2t^8 + 2t^7 + 2t^6 + 2t^5 + 2t^4 + 2t^3 + 2t^2 + 2t +` `1)/(28t^33 - 7t^32 - 7t^31 - 7t^30 - 7t^29 - 7t^28 - 7t^27 -` `7t^26 - 7t^25 - 7t^24 - 7t^23 - 7t^22 - 7t^21 - 7t^20 - 7t^19 -` `7t^18 - 7t^17 - 7t^16 - 7t^15 - 7t^14 - 7t^13 - 7t^12 - 7t^11 -` `7t^10 - 7t^9 - 7t^8 - 7t^7 - 7t^6 - 7t^5 - 7t^4 - 7t^3 - 7t^2 -` `7*t + 1)`
	CROSSREFS	`Sequence in context: A169310 A169358 A169406 * A169502 A169550 A170018` `Adjacent sequences: A169451 A169452 A169453 * A169455 A169456 A169457`
	KEYWORD	`nonn`
	AUTHOR	`John Cannon and N. J. A. Sloane, Dec 03 2009`
	STATUS	`approved`

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Last modified April 16 16:05 EDT 2024. Contains 371749 sequences. (Running on oeis4.)