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%I #12 Sep 08 2022 08:46:20
%S 1,3,4,6,8,12,16,24,32,48,64,94,120,178,232,344,448,664,864,1280,1662,
%T 2459,3202,4741,6168,9132,11880,17588,22880,33870,44068,65246,84880,
%U 125664,163484,242036,314880,466176,606478,897892,1168124,1729394,2249880,3330929,4333418,6415591,8346452,12356856,16075828,23800132
%N Growth series for group with presentation < S, T : S^2 = T^3 = (S*T)^11 = 1 >.
%H Colin Barker, <a href="/A299252/b299252.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_28">Index entries for linear recurrences with constant coefficients</a>, signature (-1,0,0,1,1,2,2,3,4,3,2,3,2,3,2,3,2,3,4,3,2,2,1,1,0,0,-1,-1).
%F G.f.: (-2*x^30 - 2*x^29 + 3*x^28 + 6*x^27 + 9*x^26 + 12*x^25 + 15*x^24 + 18*x^23 + 21*x^22 + 24*x^21 + 27*x^20 + 31*x^19 + 33*x^18 + 33*x^17 + 33*x^16 + 33*x^15 + 33*x^14 + 33*x^13 + 33*x^12 + 33*x^11 + 29*x^10 + 27*x^9 + 25*x^8 + 22*x^7 + 19*x^6 + 16*x^5 + 13*x^4 + 10*x^3 + 7*x^2 + 4*x + 1)/(x^28 + x^27 - x^24 - x^23 - 2*x^22 - 2*x^21 - 3*x^20 - 4*x^19 - 3*x^18 - 2*x^17 - 3*x^16 - 2*x^15 - 3*x^14 - 2*x^13 - 3*x^12 - 2*x^11 - 3*x^10 - 4*x^9 - 3*x^8 - 2*x^7 - 2*x^6 - x^5 - x^4 + x + 1).
%F a(n) = -a(n-1) + a(n-4) + a(n-5) + 2*a(n-6) + 2*a(n-7) + 3*a(n-8) + 4*a(n-9) + 3*a(n-10) + 2*a(n-11) + 3*a(n-12) + 2*a(n-13) + 3*a(n-14) + 2*a(n-15) + 3*a(n-16) + 2*a(n-17) + 3*a(n-18) + 4*a(n-19) + 3*a(n-20) + 2*a(n-21) + 2*a(n-22) + a(n-23) + a(n-24) - a(n-27) - a(n-28) for n>30. - _Colin Barker_, Feb 06 2018
%o (Magma) See Magma program in A298805.
%o (PARI) Vec((1 + 4*x + 7*x^2 + 10*x^3 + 13*x^4 + 16*x^5 + 19*x^6 + 22*x^7 + 25*x^8 + 27*x^9 + 29*x^10 + 33*x^11 + 33*x^12 + 33*x^13 + 33*x^14 + 33*x^15 + 33*x^16 + 33*x^17 + 33*x^18 + 31*x^19 + 27*x^20 + 24*x^21 + 21*x^22 + 18*x^23 + 15*x^24 + 12*x^25 + 9*x^26 + 6*x^27 + 3*x^28 - 2*x^29 - 2*x^30) / ((1 + x + x^2)*(1 + x^3 + x^6)*(1 - x^2 - x^4 - x^6 - x^8 + x^10 - x^12 - x^14 - x^16 - x^18 + x^20)) + O(x^60)) \\ _Colin Barker_, Feb 06 2018
%Y Cf. A008579, A298802, A298805.
%K nonn,easy
%O 0,2
%A _John Cannon_ and _N. J. A. Sloane_, Feb 06 2018
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