Original entry on oeis.org
1, 0, 0, 1, 8, 42, 215, 964, 4336, 18490, 78920, 327422, 1361450, 5561651, 22748172, 92064605, 372730314, 1498785098, 6028277742, 24137078144, 96650940881, 385889337069, 1540641044744, 6139148609668, 24462365837156, 97350374411004, 387401219371335
Offset: 0
-
f:= proc(n) option remember; `if`(n<2, 1, f(n-1)*(q^n-1)/(q-1)) end:
b:= proc(n, i) option remember; simplify(`if`(n=0 or i=1, 1,
add(b(n-i*j, i-1)/f(i)^j, j=0..n/i)))
end:
a:= n-> coeff(simplify(f(n)*b(n$2)), q, n):
seq(a(n), n=0..26);
-
f[n_] := f[n] = If[n < 2, 1, f[n - 1]*(q^n - 1)/(q - 1)];
b[n_, i_] := b[n, i] = If[n == 0 || i == 1, 1,
Sum[b[n - i*j, i - 1]/f[i]^j, {j, 0, n/i}]];
a[n_] := SeriesCoefficient[f[n]*b[n, n], {q, 0, n}];
Table[a[n], {n, 0, 26}] (* Jean-François Alcover, Apr 07 2022, after Alois P. Heinz *)
A152536
a(n) = Sum_{k=0..binomial(n,2)} (-1)^k*A152534(n,k).
Original entry on oeis.org
1, 1, 1, 2, 3, 6, 10, 23, 47, 110, 246, 617, 1602, 4035, 11481, 29927, 95503, 249926, 871030, 2316317, 8879558, 23674841, 98329551, 264329177, 1191578522, 3207278255, 15543026747, 42011308653, 218668538441, 591460307157, 3285749117475, 8905905152798, 52700813279423
Offset: 0
A152474
Triangle T(n,k) read by rows: Sum_{k=0..binomial(n,2)} T(n,k)*q^k = n!*Sum_{pi} faq(n,q)/Product_{i=1..n} e(i)!*faq(i,q)^e(i), where pi runs over all nonnegative integer solutions to e(1) + 2*e(2) + ... + n*e(n) = n and faq(i,q) = Product_{j=1..i} (q^j-1)/(q-1), i = 1..n.
Original entry on oeis.org
1, 1, 3, 1, 13, 8, 8, 1, 73, 63, 89, 78, 41, 15, 1, 501, 544, 909, 1095, 1200, 842, 680, 315, 129, 24, 1, 4051, 5225, 9734, 13799, 18709, 20441, 20520, 18101, 14831, 10200, 5891, 3199, 1109, 314, 35, 1, 37633, 55656, 112370, 177457, 270746, 352969, 442897
Offset: 0
Triangle T(n,k) begins:
1;
1;
3, 1;
13, 8, 8, 1;
73, 63, 89, 78, 41, 15, 1;
501, 544, 909, 1095, 1200, 842, 680, 315, 129, 24, 1;
...
-
{T(n,k)=local(e_q=sum(j=0,n,x^j/prod(i=1,j,(q^i-1)/(q-1)))+x*O(x^n)); n!*polcoeff(polcoeff(exp(e_q-1),n,x)*prod(j=1,n,(q^j-1)/(q-1)),k,q)} \\ Paul D. Hanna, Dec 15 2008
Showing 1-3 of 3 results.