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 A278073 Triangle read by rows, coefficients of the polynomials P(m, n) = Sum_{k=1..n} binomial(m*n, m*k)* P(m, n-k)*z with P(m, 0) = 1 and m = 3. 18
 1, 0, 1, 0, 1, 20, 0, 1, 168, 1680, 0, 1, 1364, 55440, 369600, 0, 1, 10920, 1561560, 33633600, 168168000, 0, 1, 87380, 42771456, 2385102720, 34306272000, 137225088000, 0, 1, 699048, 1160164320, 158411809920, 5105916816000, 54752810112000, 182509367040000 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,6 LINKS Table of n, a(n) for n=0..35. FORMULA E.g.f.: 1/(1-t*((1/3)*exp(x)+(2/3)*exp(-(1/2)*x)*cos((1/2)*x*sqrt(3))-1)), nonzero terms. EXAMPLE Triangle begins: [1] [0, 1] [0, 1, 20] [0, 1, 168, 1680] [0, 1, 1364, 55440, 369600] [0, 1, 10920, 1561560, 33633600, 168168000] MAPLE P := proc(m, n) option remember; if n = 0 then 1 else add(binomial(m*n, m*k)*P(m, n-k)*x, k=1..n) fi end: for n from 0 to 6 do PolynomialTools:-CoefficientList(P(3, n), x) od; # Alternatively: A278073_row := proc(n) 1/(1-t*((1/3)*exp(x)+(2/3)*exp(-(1/2)*x)*cos((1/2)*x*sqrt(3))-1)); expand(series(%, x, 3*n+1)); (3*n)!*coeff(%, x, 3*n); PolynomialTools:-CoefficientList(%, t) end: for n from 0 to 6 do A278073_row(n) od; MATHEMATICA With[{m = 3}, Table[Expand[j!*SeriesCoefficient[1/(1 - t*(MittagLefflerE[m, x^m] - 1)), {x, 0, j}]], {j, 0, 21, m}]]; Function[arg, CoefficientList[arg, t]] /@ % // Flatten PROG (Sage) R = PowerSeriesRing(ZZ, 'x') x = R.gen().O(30) @cached_function def P(m, n): if n == 0: return R(1) return expand(sum(binomial(m*n, m*k)*P(m, n-k)*x for k in (1..n))) def A278073_row(n): return list(P(3, n)) for n in (0..6): print(A278073_row(n)) # Peter Luschny, Mar 24 2020 CROSSREFS Cf. A014606 (diagonal), A243664 (row sums), A002115 (alternating row sums), A281479 (central coefficients), A327023 (refinement). Cf. A097805 (m=0), A131689 (m=1), A241171 (m=2), A278074 (m=4). Sequence in context: A072840 A091234 A221873 * A365912 A324274 A070708 Adjacent sequences: A278070 A278071 A278072 * A278074 A278075 A278076 KEYWORD nonn,tabl AUTHOR Peter Luschny, Jan 22 2017 STATUS approved

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Last modified June 22 02:28 EDT 2024. Contains 373561 sequences. (Running on oeis4.)