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A194450
Vertex number of a rectangular spiral which contains exactly between its edges the successive shells of the partitions of the positive integers.
1
0, 1, 2, 4, 6, 9, 12, 17, 21, 28, 33, 44, 50, 65, 72, 94, 102, 132, 141, 183, 193, 249, 260, 337, 349, 450, 463, 598, 612, 788, 803, 1034, 1050, 1347, 1364, 1749, 1767, 2257, 2276, 2903, 2923, 3715, 3736, 4738, 4760, 6015, 6038, 7613, 7637, 9595
OFFSET
0,3
COMMENTS
First differences give A194451, the length of the edges of the spiral. For more information see A135010 and A138121.
FORMULA
a(2n-1) = A026905(n) + A000217(n) - n, if n >= 1.
a(2n) = A026905(n) + A000217(n), if n >= 1.
KEYWORD
nonn
AUTHOR
Omar E. Pol, Nov 01 2011
STATUS
approved