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 A144061 #5 Jun 02 2025 00:33:47 %S A144061 1,1,1,1,3,2,1,5,10,6,1,7,22,42,22,1,9,38,114,198,94,1,11,58,234,638, %T A144061 1034,454,1,13,82,414,1518,3854,5902,2430,1,15,110,666,3058,10434, %U A144061 24970,36450,14214,1,17,142,1002,5522,23594,75818,172530,241638,89918 %N A144061 Eigentriangle generated from A109128, row sums = expansion of {2(exp(x)-1)}. %C A144061 Row sums = A001861: (1, 2, 6, 22, 94, 454, 2430,...) = expansion of {2(exp(x)-1)} %C A144061 Right border = A001861 shifted: (1, 1, 2, 6, 22, 94,...). %C A144061 Sum of n-th row terms = rightmost term of next row. %F A144061 T(n,k) = A109128(n,k)*A001861(k-1). %F A144061 A109128 = (2*binomial(n,k) - 1): (1; 1,1; 1,3,1; 1,5,5,1;...). %F A144061 A001861(k-1) = A001861 shifted one place, = (1, 1, 2, 6, 22, 94, 454,...). %e A144061 First few rows of the triangle = %e A144061 1; %e A144061 1, 1; %e A144061 1, 3, 2; %e A144061 1, 5, 10, 6; %e A144061 1, 7, 22, 42, 22; %e A144061 1, 9, 38, 114, 198, 94; %e A144061 1, 11, 58, 234, 638, 1034, 454; %e A144061 1, 13, 82, 414, 1518, 3854, 5902, 2430; %e A144061 1, 15, 110, 666, 3058, 10434, 24970, 36450, 14214; %e A144061 ... %e A144061 Example: row 3 = (1, 5, 10, 6) = termwise products of (1, 5, 5, 1) and (1, 1, 2, 6), where (1, 5, 5, 1) = row 3 of triangle A109128 and (1, 1, 2, 6) = the first 4 terms of A001861 shifted. %Y A144061 A109128, Cf. A001861 %K A144061 nonn,tabl %O A144061 1,5 %A A144061 _Gary W. Adamson_ & _Roger L. Bagula_, Sep 09 2008