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A032303 "EFK" (unordered, size, unlabeled) transform of 2,1,1,1,... 2
1, 2, 1, 3, 3, 4, 6, 7, 9, 11, 15, 17, 22, 26, 32, 39, 47, 55, 67, 79, 93, 111, 130, 152, 178, 208, 241, 281, 325, 375, 433, 499, 571, 657, 751, 858, 980, 1116, 1268, 1442, 1635, 1851, 2095, 2367, 2669, 3011, 3389, 3809, 4281, 4803, 5383, 6030, 6746, 7538 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Number of partitions of n into distinct parts with two kinds of one. - Andrew Howroyd, Jun 21 2018

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..1000

C. G. Bower, Transforms (2)

FORMULA

G.f.: (1+2*x) * Product_{k=2..infinity} (1+x^k).

PROG

(PARI) {my(n=60); Vec((1+2*x)*prod(k=2, n, 1+x^k + O(x*x^n)))} \\ Andrew Howroyd, Jun 21 2018

CROSSREFS

Cf. A032006.

Sequence in context: A318611 A130067 A282906 * A032215 A117363 A007307

Adjacent sequences:  A032300 A032301 A032302 * A032304 A032305 A032306

KEYWORD

nonn

AUTHOR

Christian G. Bower

EXTENSIONS

a(0)=1 prepended and terms a(50) and beyond from Andrew Howroyd, Jun 21 2018

STATUS

approved

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Last modified October 24 01:20 EDT 2018. Contains 316541 sequences. (Running on oeis4.)