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A206555
Number of 5's in the last section of the set of partitions of n.
6
0, 0, 0, 0, 1, 0, 1, 1, 2, 3, 4, 5, 8, 10, 15, 18, 26, 32, 44, 56, 73, 92, 120, 149, 193, 238, 302, 373, 469, 576, 716, 876, 1081, 1316, 1615, 1954, 2383, 2875, 3483, 4188, 5048, 6043, 7253, 8653, 10341, 12293, 14634, 17340, 20567, 24300, 28717, 33830
OFFSET
1,9
COMMENTS
Zero together with the first differences of A024789. Also number of occurrences of 5 in all partitions of n that do not contain 1 as a part. It appears that the sum of five successive terms gives the partition numbers A000041 (see A182703 and A194812).
FORMULA
It appears that A000041(n) = Sum_{j=1..5} a(n+j), n >= 0.
PROG
(Sage) A206555 = lambda n: sum(list(p).count(5) for p in Partitions(n) if 1 not in p)
CROSSREFS
Column 5 of A182703 and of A194812.
Sequence in context: A035555 A373015 A039875 * A110539 A222297 A211981
KEYWORD
nonn
AUTHOR
Omar E. Pol, Feb 09 2012
EXTENSIONS
More terms from Alois P. Heinz, Feb 20 2012
STATUS
approved