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 A117937 #14 Jun 28 2025 18:58:36 %S A117937 1,1,1,3,3,2,4,10,12,6,7,27,58,60,24,11,71,240,420,360,120,18,180,920, %T A117937 2460,3504,2520,720,29,449,3360,13020,27720,32760,20160,5040,47,1107, %U A117937 11898,64620,194184,337680,338400,181440,40320,76,2710,41268,307194,1257120,3029760,4415040 %N A117937 Triangle, rows = inverse binomial transforms of A117938 columns. %C A117937 A117936 is the companion triangle using analogous Fibonacci polynomials. Left border of A117936 = the Lucas numbers; right border = factorials. %C A117937 [Note that most of the comments here and in many related sequences by the same author refer to some unusual definition of binomial transforms for sequences starting at index 1. - _R. J. Mathar_, Jul 05 2012] %F A117937 Rows of the triangle are inverse binomial transforms of A117938 columns. A117938 columns are generated from f(x), Lucas polynomials: (1); (x); (x^2 + 2); (x^3 + 3x); (x^4 + 4x + 2);... %e A117937 First few rows of the triangle are: %e A117937 1; %e A117937 1, 1; %e A117937 3, 3, 2; %e A117937 4, 10, 12, 6; %e A117937 7, 27, 58, 60, 24; %e A117937 11, 71, 240, 420, 360, 120; %e A117937 ... %e A117937 For example, row 4: (4, 10, 12, 6) = the inverse binomial transform of column 4 of A117938: (4, 14, 36, 76, 140...), being f(x), x =1,2,3...using the Lucas polynomial x^3 + 3x. %p A117937 A117937 := proc(n,k) %p A117937 add( A117938(n+i,n)*binomial(k-1,i)*(-1)^(1+i-k),i=0..k-1) ; %p A117937 end proc: %p A117937 seq(seq(A117937(n,k),k=1..n),n=1..13) ; # _R. J. Mathar_, Aug 16 2019 %Y A117937 Cf. A117936, A117938. %K A117937 nonn,tabl,easy %O A117937 1,4 %A A117937 _Gary W. Adamson_, Apr 04 2006