This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A201549 #37 Mar 21 2025 09:25:36 %S A201549 1,1,11,91,891,8801,88913,908755,9377467,97464799,1018872811, %T A201549 10701243741,112835748609,1193692544825,12663809507129, %U A201549 134678108144591,1435345208419771,15326122342137035,163920458145421109 %N A201549 Number of arrays of n integers in -5..5 with sum zero. %C A201549 Also largest coefficient of (1+x+...+x^10)^n. - _Vaclav Kotesovec_, Aug 09 2013 %H A201549 Seiichi Manyama, <a href="/A201549/b201549.txt">Table of n, a(n) for n = 0..500</a> (terms 1..210 from R. H. Hardin) [It was suggested that the initial terms of this b-file were wrong, but in fact they are correct. - _N. J. A. Sloane_, Jan 19 2019] %H A201549 <a href="/index/Ce#cfn">Index entries for sequences of k-nomial coefficients</a> %F A201549 From _Vaclav Kotesovec_, Aug 09 2013: (Start) %F A201549 Recurrence: 726*(n-2) * (n-1) * (2*n-1) * (3*n-7) * (3*n-1) * (5*n-19) * (5*n-9) * (5*n-8) * (6*n-25) * (6*n-13) * (6*n-1) * (2280*n^4 - 18164*n^3 + 49523*n^2 - 53013*n + 18900)*a(n-3) - 3*(2*n-1) * (3*n-7) * (3*n-1) * (5*n-19) * (5*n-14) * (5*n-9) * (5*n-8) * (6*n-25) * (6*n-19) * (6*n-13) * (6*n-1) * (4651*n^4 - 18604*n^3 + 27451*n^2 - 17694*n + 4200)*a(n-1) + 3993*(n-3) * (n-2) * (n-1) * (3*n-4) * (5*n-14) * (5*n-4) * (5*n-3) * (6*n-19) * (6*n-7) * (6*n-1) * (5310*n^5 - 65313*n^4 + 295326*n^3 - 594091*n^2 + 499480*n - 112320)*a(n-4) - 33*(n-1) * (3*n-4) * (5*n-19) * (5*n-14) * (5*n-4) * (5*n-3) * (6*n-25) * (6*n-19) * (6*n-7) * (45306*n^6 - 385101*n^5 + 1267841*n^4 - 2002349*n^3 + 1504595*n^2 - 451668*n + 42120)*a(n-2) - 161051*(n-5) * (n-4) * (n-3) * (n-2) * (n-1) * (3*n-4) * (3*n-1) * (5*n-14) * (5*n-9) * (5*n-4) * (5*n-3) * (6*n-19) * (6*n-13) * (6*n-7) * (6*n-1)*a(n-6) - 43923*(n-4) * (n-3) * (n-2) * (n-1) * (2*n-1) * (3*n-7) * (3*n-1) * (5*n-19) * (5*n-9) * (5*n-8) * (5*n-4) * (6*n-25) * (6*n-13) * (6*n-7) * (6*n-1)*a(n-5) + 5*n*(3*n-7) * (3*n-4) * (5*n-19) * (5*n-14) * (5*n-9) * (5*n-8) * (5*n-4) * (5*n-3) * (5*n-2) * (5*n-1) * (6*n-25) * (6*n-19) * (6*n-13) * (6*n-7)*a(n) = 0. %F A201549 a(n) ~ 11^n / sqrt(20*Pi*n). (End) %F A201549 a(n) = Sum_{k = 0..floor(n/2)} (-1)^k * binomial(n, k)*binomial(6*n-11*k-1, n-1). - _Peter Bala_, Oct 16 2024 %e A201549 Some solutions for n=6 %e A201549 .-5...-5...-1...-2...-1....3....4....1....1...-1....3....4....5....0...-5....5 %e A201549 .-2....4...-1....1....0...-4....2....1....1...-5...-4...-4....1...-3....5...-5 %e A201549 ..0...-3....1....3...-1...-4....0...-1....2...-4...-4...-4...-5...-3...-2....5 %e A201549 ..4....3....3...-3....4....5....1....2....2....5....3....5...-3....2....2...-5 %e A201549 ..5...-4...-1...-4...-4....1...-2...-4...-5....2....0....4....1....4...-4....3 %e A201549 .-2....5...-1....5....2...-1...-5....1...-1....3....2...-5....1....0....4...-3 %p A201549 seq(add((-1)^k * binomial(n, k)*binomial(6*n-11*k-1, n-1), k = 0..floor(n/2)), n = 0..20); # _Peter Bala_, Oct 16 2024 %t A201549 Table[Coefficient[Expand[Sum[x^j,{j,0,10}]^n],x^(5*n)],{n,1,20}] (* _Vaclav Kotesovec_, Aug 09 2013 *) %o A201549 (PARI) {a(n) = polcoeff((sum(k=0, 10, x^k))^n, 5*n, x)} \\ _Seiichi Manyama_, Dec 14 2018 %Y A201549 Column 5 of A201552. Row 11 of A077042. %K A201549 nonn %O A201549 0,3 %A A201549 _R. H. Hardin_, Dec 02 2011 %E A201549 a(0)=1 prepended by _Seiichi Manyama_, Dec 14 2018