cp's OEIS Frontend

A214364 Irregular triangle read by rows n lists the values k of all decompositions of 2n into unordered sums of two k-almost primes.

%I A214364 #14 Jul 29 2012 21:53:32
%S A214364 0,1,1,1,2,1,2,1,1,2,1,2,1,1,1,2,3,2,1,1,2,1,2,1,3,2,1,1,1,1,1,2,2,1,
%T A214364 2,1,2,1,3,1,1,2,3,1,2,2,1,2,1,3,1,2,1,2,2,3,1,4,1,1,2,1,1,1,1,3,2,1,
%U A214364 2,2,1,3,2,1,3,3,1,1,2,1,3,2,2,4,1,3,2,1,2,1,3,1,2,1,2,1,2,2,1,2
%N A214364 Irregular triangle read by rows n lists the values k of all decompositions of 2n into unordered sums of two k-almost primes.
%C A214364 Row n has 1+A214154(n) entries, if n <> 1, where the '1' means the splitting 2*n=n+n into non-distinct k-almost primes is also registered here, but not in A214154. Therefore the last entry in row n is A001222(n) for n > 3.
%C A214364 Row sums are 0, 1, 1, 3, 4, 3, 4, 7, 6, 9, 3, 10, 8, 9, 12, 13, 6, 16, 10, 19, 12, 11, 9, 25, 16, 16, 15, 19, 14, 31, 14, 30, 14, 15, 24,..
%e A214364 If written as a triangle:
%e A214364 0,
%e A214364 1,
%e A214364 1,
%e A214364 1, 2,
%e A214364 1, 2, 1,
%e A214364 1, 2,
%e A214364 1, 2, 1,
%e A214364 1, 1, 2, 3,
%e A214364 2, 1, 1, 2,
%e A214364 1, 2, 1, 3, 2,
%e A214364 1, 1, 1,
%e A214364 1, 1, 2, 2, 1, 3,
%e A214364 1, 2, 1, 3, 1,
%e A214364 1, 2, 3, 1, 2,
%e A214364 2, 1, 2, 1, 3, 1, 2,
%e A214364 1, 2, 2, 3, 1, 4,
%e A214364 1, 1, 2, 1, 1,
%e A214364 1, 1, 3, 2, 1, 2, 2, 1, 3.
%Y A214364 Cf. A078840. - _N. J. A. Sloane_, Jul 29 2012
%K A214364 nonn,tabf,less
%O A214364 1,5
%A A214364 _Juri-Stepan Gerasimov_, Jul 23 2012