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 A373733 #30 Jul 22 2024 06:30:50 %S A373733 0,1,10,55,210,630,1596,3570,7260,13695,24310,41041,66430,103740, %T A373733 157080,231540,333336,469965,650370,885115,1186570,1569106,2049300, %U A373733 2646150,3381300,4279275,5367726,6677685,8243830,10104760,12303280 %N A373733 Triangular numbers with tetrahedral indices: a(n) = (1/72) * (n*(n+1)*(n+2)*(n+3)*(n^2+2)). %H A373733 Paolo Xausa, <a href="/A373733/b373733.txt">Table of n, a(n) for n = 0..10000</a> %H A373733 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (7,-21,35,-35,21,-7,1). %F A373733 a(n) = A000217(A000292(n)). %F A373733 a(n) = A000292(n) + A054563(n). %t A373733 PolygonalNumber[Binomial[Range[2, 50], 3]] (* _Paolo Xausa_, Jul 22 2024 *) %o A373733 (PARI) a(n)=n*(n+1)*(n+2)*(n+3)*(n^2+2)/72 \\ _Charles R Greathouse IV_, Jul 10 2024 %o A373733 (Python) %o A373733 from math import comb %o A373733 def A373733(n): return comb(comb(n+2,3)+1,2) # _Chai Wah Wu_, Jul 10 2024 %Y A373733 Cf. A000292, A000217, A054563. %K A373733 nonn,easy %O A373733 0,3 %A A373733 _J.S. Seneschal_, Jun 17 2024