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 A143420 #7 May 26 2024 16:11:46 %S A143420 1,8,55,370,2520,17472,123151,880070,6360706,46402312,341153384, %T A143420 2524722928,18789734496,140521154048,1055383259791,7956220907758, %U A143420 60179579570382,456545145078408,3472804505717170 %N A143420 Row sums of triangle A373101. %C A143420 Each term in the sequence is a sum of tetrahedral numbers. %C A143420 The underlying triangle mentioned as A143419 was lost and is now restored in A373101. - _Georg Fischer_, May 23 2024 %e A143420 a(5) = 370 = (20 + 165 + 165 + 20) = C(6,3) + C(11,3) + C(11,8) + C(6,3). %p A143420 seq(add((binomial(n,k)^3 - binomial(n,k))/6,k=1..n-1),n=2..20); # _Georg Fischer_, May 23 2024 %Y A143420 Cf. A108958 (row sums of A143418), A373101. %K A143420 nonn,easy %O A143420 2,2 %A A143420 _Gary W. Adamson_, Aug 14 2008 %E A143420 Definition changed, a(7) corrected and more terms from _Georg Fischer_, May 23 2024