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 A225203 #15 Feb 22 2025 23:59:27 %S A225203 1,0,2,1,0,3,0,0,0,4,1,2,0,0,5,0,0,0,0,0,6,1,0,3,0,0,0,7,0,2,0,0,0,0, %T A225203 0,8,1,0,0,4,0,0,0,0,9,0,0,0,0,0,0,0,0,0,10,1,2,3,0,5,0,0,0,0,0,11,0, %U A225203 0,0,0,0,0,0,0,0,0,0,12,1,0,0,0,0,6,0,0,0,0,0,0,13 %N A225203 Table T(n,k) composed of rows equal to: n * (the characteristic function of the multiples of (n+1)), read by downwards antidiagonals. %C A225203 Column k =1 of the table is the integers, from n=1 in row 1. %C A225203 The n-th row of the table is a repeating pattern, starting with the value of n followed by n instances of zero, as created by the characteristic function of the multiples of (n+1). %C A225203 Sums of the antidiagonals produce A065608. %C A225203 Row 1 is A059841, row 2 = 2*A079978, row 3 = 3*A121262, row 4 = 4*A079998, row 5 = 5*A079979, row 6 = 6*A082784, row 7 = 7*|A014025|. - _Boris Putievskiy_, May 08 2013 %F A225203 From _Boris Putievskiy_, May 08 2013: (Start) %F A225203 As table T(n,k) = n*(floor((n+k)/(n+1))-floor((n+k-1)/(n+1))). %F A225203 As linear sequence a(n) = A002260(n)*(floor(A003057(n))/(A002260(n)+1)-floor(A002024(n))/(A002260(n)+1)); a(n) = i*(floor((t+2)/(i+1))-floor((t+1)/(i+1))), where i=n-t*(t+1)/2, t=floor((-1+sqrt(8*n-7))/2). (End) %e A225203 Table begins: %e A225203 1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0 ... %e A225203 2,0,0,2,0,0,2,0,0,2,0,0,2,0,0,2,0,0 ... %e A225203 3,0,0,0,3,0,0,0,3,0,0,0,3,0,0,0,3,0 ... %e A225203 4,0,0,0,0,4,0,0,0,0,4,0,0,0,0,4,0,0 ... %e A225203 5,0,0,0,0,0,5,0,0,0,0,0,5,0,0,0,0,0 ... %e A225203 6,0,0,0,0,0,0,6,0,0,0,0,0,0,6,0,0,0 ... %e A225203 7,0,0,0,0,0,0,0,7,0,0,0,0,0,0,0,7,0 ... %e A225203 8,0,0,0,0,0,0,0,0,8,0,0,0,0,0,0,0,0 ... %e A225203 9,0,0,0,0,0,0,0,0,0,9,0,0,0,0,0,0,0 ... %Y A225203 Cf. A065608, A002024, A002260, A003057, A059841, A079978, A121262, A079998, A079979, A082784, A014025. %K A225203 nonn,tabl,easy %O A225203 1,3 %A A225203 _Richard R. Forberg_, May 01 2013 %E A225203 More terms from _Jason Yuen_, Feb 22 2025