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A172033
Number of partitions of n into distinct parts that are 1 or even, i.e., into distinct terms of A004277.
2
1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 8, 8, 10, 10, 12, 12, 15, 15, 18, 18, 22, 22, 27, 27, 32, 32, 38, 38, 46, 46, 54, 54, 64, 64, 76, 76, 89, 89, 104, 104, 122, 122, 142, 142, 165, 165, 192, 192, 222, 222, 256, 256, 296, 296, 340, 340, 390, 390, 448, 448
OFFSET
0,7
COMMENTS
A000009 repeated: a(n) = A000009(floor(n/2)).
FORMULA
G.f.: (1+q) * Product_{n>=1} (1 + q^(2*n)). - Joerg Arndt, Mar 11 2014
EXAMPLE
a(12) = #{12, 10+2, 8+4, 6+4+2} = 4;
a(13) = #{12+1, 10+2+1, 8+4+1, 6+4+2+1} = 4;
a(14) = #{14, 12+2, 10+4, 8+6, 8+4+2} = 5.
PROG
(PARI) my(N=68, q='q+O('q^N)); Vec( (1+q)*prod(n=1, N, 1+q^(2*n)) ) \\ Joerg Arndt, Mar 11 2014
CROSSREFS
Cf. A025065.
Sequence in context: A279135 A053266 A112217 * A214131 A229977 A094994
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jan 23 2010
STATUS
approved

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