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A132456 Number of partitions of n into composite parts such that succeeding parts have a common prime factor. 2

%I #7 May 30 2013 09:58:33

%S 1,0,0,0,1,0,1,0,2,1,2,0,4,0,4,2,7,0,9,1,12,4,14,1,23,4,24,9,35,3,46,

%T 7,56,18,68,14,99,16,107,36,145,24,186,39,219,72,270,56,361,84,408,

%U 134,514,117,655,173,761,244,926,238,1194,312,1347,458,1669,458,2073,588,2389

%N Number of partitions of n into composite parts such that succeeding parts have a common prime factor.

%C a(n) <= A023895(n).

%H Alois P. Heinz, <a href="/A132456/b132456.txt">Table of n, a(n) for n = 0..1000</a>

%e a(19) = #{9+6+4} = 1, A023895(19) = #{15+4, 10+9, 9+6+4} = 3;

%e a(20) = A023895(20) = 12;

%e a(21) = #{21, 15+6, 12+9, 9+6+6} = 4, A023895(21) = 6;

%K nonn

%O 0,9

%A _Reinhard Zumkeller_, Aug 22 2007

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Last modified April 19 16:52 EDT 2024. Contains 371794 sequences. (Running on oeis4.)