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 A278196 Partition numbers (A000041) of the form 2^2 * k for odd k. 7

%I

%S 2436,5604,451276,715220,831820,1300156,7089500,12132164,15796476,

%T 26543660,190569292,483502844,761002156,851376628,1327710076,

%U 2841940500,3519222692,9035836076,54770336324,1280011042268,1820701100652,3972999029388,6085253859260

%N Partition numbers (A000041) of the form 2^2 * k for odd k.

%C Also partition numbers having twice as many even divisors as odd divisors.

%C A subsequence of A225324.

%H Colin Barker, <a href="/A278196/b278196.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[PartitionsP@ Range@ 210, Count[#, k_ /; EvenQ@ k] == 2 Count[#, k_ /; OddQ@ k] &@ Divisors@ # &] (* _Michael De Vlieger_, Nov 15 2016 *)

%o (PARI) maxk=300; L=List(); for(k=1, maxk, p=numbpart(k); if(p%2^2==0 & p\2^2%2==1, listput(L, p))); Vec(L)

%Y Cf. A275029, A278197, A278198, A278199, A278200, A278201.

%K nonn

%O 1,1

%A _Colin Barker_, Nov 15 2016

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Last modified October 18 00:21 EDT 2019. Contains 328135 sequences. (Running on oeis4.)