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 A302187 #24 Nov 25 2024 12:36:43
%S A302187 1,2,8,30,138,620,3060,14910,76650,390852,2063376,10832052,58264668,
%T A302187 312123240,1702423008,9256786110,51036229530,280696824980,
%U A302187 1560925457520,8663089672380,48512836025940,271229902496280,1527733861191720,8593482390429300,48642125421855420,275014629509319000
%N A302187 Number of 3D walks of type bcc.
%C A302187 See Dershowitz (2017) for precise definition.
%H A302187 Nachum Dershowitz, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL20/Dershowitz/dersh3.html">Touchard's Drunkard</a>, Journal of Integer Sequences, Vol. 20 (2017), #17.1.5.
%F A302187 a(n) = Sum_{k=0..n} binomial(n, k)*A001405(k)*A018224(n-k). - _Mélika Tebni_, Nov 25 2024
%o A302187 (Python)
%o A302187 from math import comb as binomial
%o A302187 def a(n):
%o A302187 return sum(binomial(n, k)*binomial(k, k//2)*binomial(n-k, (n-k)//2)**2 for k in range(n+1))
%o A302187 print([a(n) for n in range(26)]) # _Mélika Tebni_, Nov 25 2024
%Y A302187 Cf. A000108, A000984, A002212, A002896, A005572, A026375, A064037, A081671, A138547, A145847, A145867, A150500, A202814.
%Y A302187 Cf. A001405, A018224.
%K A302187 nonn,walk
%O A302187 0,2
%A A302187 _N. J. A. Sloane_, Apr 09 2018
%E A302187 a(12)-a(25) from _Nachum Dershowitz_, Aug 03 2020