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 A086400 #11 Apr 21 2025 02:31:15
%S A086400 1,4,18,527,3218,138634,957857,49120018,20473889132,156766505690,
%T A086400 74324776203270,4686290685410776,37541445026997947,
%U A086400 2445882966702428971,1327937505693018342712,743757817682170309535791,6166664829842021655267818,3568011384191503508502528953,250506784439047192764704514076
%N A086400 (1/p)*(M(p)-1) where p runs through the odd primes and M(p) = A001006(p) is the p-th Motzkin number.
%H A086400 Amiram Eldar, <a href="/A086400/b086400.txt">Table of n, a(n) for n = 1..317</a>
%t A086400 motz[0] = motz[1] = 1; motz[n_] := motz[n] = ((2*n + 1)*motz[n-1] + 3*(n-1)*motz[n-2])/(n+2); Table[(motz[p]-1)/p, {p, Prime[Range[2, 20]]}] (* _Amiram Eldar_, Apr 20 2025 *)
%Y A086400 Cf. A001006.
%K A086400 nonn
%O A086400 1,2
%A A086400 _Benoit Cloitre_, Sep 06 2003
%E A086400 Data corrected by _Amiram Eldar_, Apr 20 2025