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a(n) is the total number of even parts in all partitions of n into consecutive parts.
2

%I #24 Dec 10 2021 11:38:03

%S 0,1,1,1,1,2,1,1,3,3,1,2,1,3,5,1,1,4,1,4,6,3,1,2,3,3,6,4,1,7,1,1,6,3,

%T 7,6,1,3,6,4,1,7,1,5,12,3,1,2,5,6,6,5,1,9,8,4,6,3,1,9,1,3,14,1,8,9,1,

%U 5,6,9,1,7,1,3,13,5,11,10,1,4,10,3,1,9,8,3,6,6,1,18

%N a(n) is the total number of even parts in all partitions of n into consecutive parts.

%H Antti Karttunen, <a href="/A329322/b329322.txt">Table of n, a(n) for n = 1..20000</a>

%F a(n) = A204217(n) - A329321(n).

%e For n = 15 there are four partitions of 15 into consecutive part, they are [15], [8, 7], [6, 5, 4], [5, 4, 3, 2, 1]. In total there are five even parts, they are [8, 6, 4, 4, 2], so a(15) = 5.

%o (PARI) A329322(n) = { my(i=2, t=!(n%2)); n--; while(n>0, if(!(n%i), t += (!((n/i)%2)+i)\2); n-=i; i++); t }; \\ (After _David A. Corneth_'s program for A204217) - _Antti Karttunen_, Dec 09 2021

%Y Cf. A204217 (total number of parts).

%Y Cf. A001227, A237048, A245579, A285898, A285914, A286000, A286001, A299765, A328361, A328365, A329321.

%K nonn

%O 1,6

%A _Omar E. Pol_, Nov 10 2019