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 A145573 #9 Aug 28 2019 08:50:48 %S A145573 0,1,0,1,0,0,1,0,1,0,0,1,0,1,0,0,0,0,1,0,1,1,0,0,1,0,0,0,0,1,0,1,1,0, %T A145573 0,0,1,0,0,0,0,0,0,0,1,0,1,1,1,0,0,0,1,1,0,0,0,0,1,0,0,0,0,0,0,0,1,0, %U A145573 1,1,1,0,0,0,0,1,1,1,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,1,0,1,1,1,1,0,0,0 %N A145573 Characteristic partition array for partitions without part 1. %C A145573 The partitions are ordered according to Abramowitz-Stegun (A-St order). See e.g. A036040 for the reference, pp. 831-2. %C A145573 The row lengths of this array are p(n)=A000041(n) (number of partitions of n). %C A145573 The entries of row n are grouped together for partitions with rising parts number m from 1 to n. The number of partitions of n with m parts is p(n,m)= A008284(n,m), m=1..n, n>=1. %C A145573 For the array without zeros see A145574. %H A145573 W. Lang and M. Sjodahl <a href="/A145573/a145573.txt">First 10 rows of the array and row sums.</a> %F A145573 As array: a(n,k)=1 if the k-th partition of n in A-St order has no part 1, and a(n,k)=0 else. %F A145573 Translated into the sequence a(m) entry: a(n,k) = a(sum(p(k),k=1..n)+k). %e A145573 [0],[1,0],[1,0,0],[1,0,1,0,0],[1,0,1,0,0,0,0],... %e A145573 a(4,3) = a(1+2+3+3) = a(9) = 1 because a(4,3) belongs to the partition [2^2]=[2,2] of n=4 which has no part 1. %Y A145573 Cf. A145574 (without zeros). A002865 (row sums). %K A145573 nonn,easy,tabf %O A145573 1,1 %A A145573 _Wolfdieter Lang_ and Malin Sjodahl, Mar 06 2009