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 A348662 #36 Nov 01 2021 04:02:30
%S A348662 1,-3,8,-30,128,-518,2048,-8172,32768,-131142,524288,-2096900,8388608,
%T A348662 -33555356,134217728,-536867480,2147483648,-8589947462,34359738368,
%U A348662 -137438904852,549755813888,-2199023440308,8796093022208,-35184371383400,140737488355328
%N A348662 a(n) = Sum_{m=0..n} (-1)^m * ( Sum_{k=0..m} binomial(n,k) )^2.
%H A348662 Seiichi Manyama, <a href="/A348662/b348662.txt">Table of n, a(n) for n = 0..1000</a>
%F A348662 a(n) = -(4/(n-1)) * ( 2 * (n-2) * a(n-1) + (5 * n - 14) *a(n-2) + 8 * (n-3) * a(n-3) + 16 * (n-4) * a(n-4) ) for n > 3.
%F A348662 a(n) ~ (-1)^n * 2^(2*n-1). - _Vaclav Kotesovec_, Nov 01 2021
%t A348662 a[n_] := Sum[(-1)^m * Sum[Binomial[n, k], {k, 0, m}]^2, {m, 0, n}]; Array[a, 25, 0] (* _Amiram Eldar_, Oct 28 2021 *)
%o A348662 (PARI) a(n) = sum(m=0, n, (-1)^m*sum(k=0, m, binomial(n, k))^2);
%Y A348662 Sum_{m=0..n} ( Sum_{k=0..m} (-1)^m * binomial(n,k) )^E: (-1)^n * A011782(n) (E=1), this sequence (E=2), A348457 (E=3).
%Y A348662 Cf. A003583.
%K A348662 sign
%O A348662 0,2
%A A348662 _Seiichi Manyama_, Oct 28 2021