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 A135089 #24 Mar 27 2022 18:59:46 %S A135089 1,5,5,5,10,5,5,15,15,5,5,20,30,20,5,5,25,50,50,25,5,5,30,75,100,75, %T A135089 30,5,5,35,105,175,175,105,35,5,5,40,140,280,350,280,140,40,5,5,45, %U A135089 180,420,630,630,420,180,45,5,5,50,225,600,1050,1260,1050,600,225,50,5 %N A135089 Triangle T(n,k) = 5*binomial(n,k) with T(0,0) = 1, read by rows. %C A135089 Row sums = A020714 (except for the first term). %C A135089 Triangle T(n,k), 0 <= k <= n, read by rows given by (5, -4, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (5, -4, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938. - _Philippe Deléham_, Nov 24 2013 %H A135089 G. C. Greubel, <a href="/A135089/b135089.txt">Table of n, a(n) for the first 50 rows</a> %F A135089 T(n,k) = 5*binomial(n,k), n > 0, 0 <= k <= n. %F A135089 Equals 2*A134059(n,k) - A007318(n,k). %F A135089 G.f.: (1+4*x+4*x*y)/(1-x-x*y). - _Philippe Deléham_, Nov 24 2013 %F A135089 Sum_{k=0..n} T(n,k) = A020714(n) - 4*[n=0]. - _G. C. Greubel_, May 03 2021 %e A135089 First few rows of the triangle: %e A135089 1; %e A135089 5, 5; %e A135089 5, 10, 5; %e A135089 5, 15, 15, 5; %e A135089 5, 20, 30 20, 5; %e A135089 5, 25, 50, 50, 25, 5; %e A135089 5, 30, 75, 100, 75, 30, 5. %t A135089 Table[5*Binomial[n,k] -4*Boole[n==0], {n, 0, 12}, {k, 0, n}]//Flatten (* _G. C. Greubel_, Sep 22 2016; May 03 2021 *) %o A135089 (Magma) [1] cat [5*Binomial(n,k): k in [0..n], n in [1..12]]; // _G. C. Greubel_, May 03 2021 %o A135089 (Sage) %o A135089 def A135089(n,k): return 5*binomial(n,k) - 4*bool(n==0) %o A135089 flatten([[A135089(n,k) for k in (0..n)] for n in (0..12)]) # _G. C. Greubel_, May 03 2021 %Y A135089 Cf. A007318, A020714, A132200, A134058, A134059. %K A135089 nonn,tabl %O A135089 0,2 %A A135089 _Gary W. Adamson_, Nov 18 2007