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 A354293 #24 May 25 2022 02:55:35
%S A354293 3,4,-1,23,21,-1,188,65,1010,2231,-1,-1,1326,389,1092,13196,1450,-1,
%T A354293 40466,85553,665,-1,5139193,333,-1,408241,-1,3072,6702,1393,5832,935,
%U A354293 1071,77421,292187,775383,493135,4185,1784560,10632,7935,743003,13418,64499,1746798,12176,152551
%N A354293 a(n) is the least integer m such that A001006(m) is divisible by prime(n)^2 or -1 if no such m exists.
%H A354293 Chai Wah Wu, <a href="/A354293/b354293.txt">Table of n, a(n) for n = 1..52</a>
%H A354293 Armin Straub, <a href="https://arxiv.org/abs/2205.09902">On congruence schemes for constant terms and their applications</a>, arXiv:2205.09902 [math.NT], 2022. see Theorem 3.3 p. 13.
%o A354293 (PARI) catalan(n) = binomial(2*n, n)/(n+1);
%o A354293 M(n) = sum(k=0, n, (-1)^(n-k)*binomial(n, k)*catalan(k+1));
%o A354293 a(n) = {my(p=prime(n)); if (p>200, error); if (vecsearch([5, 13, 31, 37, 61, 79, 97, 103], p), return (-1)); my(k=1); while (M(k) % p^2, k++); k;};
%Y A354293 Cf. A000040, A001006, A001248, A354292.
%Y A354293 Motzkin numbers A001006 read mod 2,3,4,5,6,7,8,11: A039963, A039964, A299919, A258712, A299920, A258711, A299918, A258710.
%K A354293 sign
%O A354293 1,1
%A A354293 _Michel Marcus_, May 23 2022
%E A354293 a(16)-a(38) from _Daniel Suteu_, May 23 2022
%E A354293 a(39)-a(47) from _Chai Wah Wu_, May 23 2022