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 A266781 Molien series for invariants of finite Coxeter group A_12. 11
 1, 0, 1, 1, 2, 2, 4, 4, 7, 8, 12, 14, 21, 24, 33, 40, 53, 63, 83, 98, 126, 150, 188, 223, 278, 327, 401, 473, 573, 672, 809, 944, 1126, 1312, 1551, 1800, 2118, 2446, 2859, 3295, 3829, 4395, 5086, 5817, 6699, 7642, 8760, 9961, 11380, 12898, 14678, 16596, 18819, 21217, 23987, 26971, 30397, 34099, 38316, 42877, 48058, 53649, 59972, 66811 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS The Molien series for the finite Coxeter group of type A_k (k >= 1) has G.f. = 1/Prod_{i=2..k+1} (1-x^i). Note that this is the root system A_k not the alternating group Alt_k. REFERENCES J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See Table 3.1, page 59. LINKS Ray Chandler, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (0, 1, 1, 1, 0, 0, -1, -1, -1, -1, -1, 0, 0, -1, 0, 1, 2, 3, 3, 3, 2, 0, -1, -2, -3, -4, -4, -5, -4, -3, -1, 1, 3, 5, 7, 7, 6, 5, 3, 2, -1, -4, -6, -7, -8, -7, -6, -4, -1, 2, 3, 5, 6, 7, 7, 5, 3, 1, -1, -3, -4, -5, -4, -4, -3, -2, -1, 0, 2, 3, 3, 3, 2, 1, 0, -1, 0, 0, -1, -1, -1, -1, -1, 0, 0, 1, 1, 1, 0, -1). FORMULA G.f.: 1/((1-t^2)*(1-t^3)*(1-t^4)*(1-t^5)*(1-t^6)*(1-t^7)*(1-t^8)*(1-t^9)*(1-t^10)*(1-t^11)*(1-t^12)*(1-t^13)). MAPLE S:=series(1/mul(1-x^j, j=2..13)), x, 75): seq(coeff(S, x, j), j=0..70); # G. C. Greubel, Feb 04 2020 MATHEMATICA CoefficientList[Series[1/Product[1-x^j, {j, 2, 13}], {x, 0, 70}], x] (* G. C. Greubel, Feb 04 2020 *) PROG (PARI) Vec( 1/prod(j=2, 13, 1-x^j) +O('x^70) ) \\ G. C. Greubel, Feb 04 2020 (MAGMA) R:=PowerSeriesRing(Integers(), 70); Coefficients(R!( 1/(&*[1-x^j: j in [2..13]]) )); // G. C. Greubel, Feb 04 2020 (Sage) def A266781_list(prec):     P. = PowerSeriesRing(ZZ, prec)     return P( 1/prod(1-x^j for j in (2..13)) ).list() A266781_list(70) # G. C. Greubel, Feb 04 2020 CROSSREFS Molien series for finite Coxeter groups A_1 through A_12 are A059841, A103221, A266755, A008667, A037145, A001996, and A266776-A266781. Sequence in context: A035949 A240014 A266780 * A035955 A240015 A035962 Adjacent sequences:  A266778 A266779 A266780 * A266782 A266783 A266784 KEYWORD nonn AUTHOR N. J. A. Sloane, Jan 11 2016 STATUS approved

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Last modified February 24 00:38 EST 2020. Contains 332195 sequences. (Running on oeis4.)