|
%I #20 Sep 07 2023 02:22:26
%S 1,-14,91,-364,987,-1820,1897,754,-8008,18928,-26845,19460,15015,
%T -76272,141065,-163072,90727,99386,-368277,602616,-643734,358190,
%U 274547,-1101100,1801086,-1982330,1344525,148316,-2163590,4032756,-4938843,4216576
%N Expansion of (Product_{j>=1} (1-(-x)^j) - 1)^14 in powers of x.
%H Alois P. Heinz, <a href="/A047639/b047639.txt">Table of n, a(n) for n = 14..10000</a>
%H H. Gupta, <a href="https://doi.org/10.1112/jlms/s1-39.1.433">On the coefficients of the powers of Dedekind's modular form</a>, J. London Math. Soc., 39 (1964), 433-440.
%H H. Gupta, <a href="/A001482/a001482.pdf">On the coefficients of the powers of Dedekind's modular form</a> (annotated and scanned copy)
%F a(n) = [x^n]( QPochhammer(-x) - 1 )^14. - _G. C. Greubel_, Sep 07 2023
%p g:= proc(n) option remember; `if`(n=0, 1, add(add([-d, d, -2*d, d]
%p [1+irem(d, 4)], d=numtheory[divisors](j))*g(n-j), j=1..n)/n)
%p end:
%p b:= proc(n, k) option remember; `if`(k=0, 1, `if`(k=1, `if`(n=0, 0, g(n)),
%p (q-> add(b(j, q)*b(n-j, k-q), j=0..n))(iquo(k, 2))))
%p end:
%p a:= n-> b(n, 14):
%p seq(a(n), n=14..45); # _Alois P. Heinz_, Feb 07 2021
%t nmax=45; CoefficientList[Series[(Product[(1-(-x)^j), {j,nmax}] - 1)^14, {x,0,nmax}], x]//Drop[#, 14] & (* _Ilya Gutkovskiy_, Feb 07 2021 *)
%t With[{k=14}, Drop[CoefficientList[Series[(QPochhammer[-x] -1)^k, {x,0, 75}], x], k]] (* _G. C. Greubel_, Sep 07 2023 *)
%o (Magma)
%o m:=80;
%o R<x>:=PowerSeriesRing(Integers(), m);
%o Coefficients(R!( ((&*[1-(-x)^j: j in [1..m+2]]) -1)^(14) )); // _G. C. Greubel_, Sep 07 2023
%o (SageMath)
%o from sage.modular.etaproducts import qexp_eta
%o m=75; k=14;
%o def f(k,x): return (-1 + qexp_eta(QQ[['q']], m+2).subs(q=-x) )^k
%o def A047639_list(prec):
%o P.<x> = PowerSeriesRing(QQ, prec)
%o return P( f(k,x) ).list()
%o a=A047639_list(m); a[k:] # _G. C. Greubel_, Sep 07 2023
%o (PARI) my(x='x+O('x^40)); Vec((eta(-x)-1)^14) \\ _Joerg Arndt_, Sep 07 2023
%Y Cf. A001482 - A001488, A001490, A047638, A047640 - A047649, A047654, A047655, A341243.
%K sign
%O 14,2
%A _N. J. A. Sloane_
%E Definition and offset edited by _Ilya Gutkovskiy_, Feb 07 2021
|
