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A161777
n-th nonprime*(n-th nonprime-1)/2
0
0, 6, 15, 28, 36, 45, 66, 91, 105, 120, 153, 190, 210, 231, 276, 300, 325, 351, 378, 435, 496, 528, 561, 595, 630, 703, 741, 780, 861, 946, 990, 1035, 1128, 1176, 1225, 1275, 1326, 1431, 1485, 1540, 1596, 1653, 1770, 1891, 1953, 2016, 2080, 2145, 2278, 2346
OFFSET
1,2
FORMULA
a(n) = A000217(A018252(n)-1). [From R. J. Mathar, May 21 2010]
CROSSREFS
Sequence in context: A335267 A349476 A242454 * A117519 A091012 A241988
KEYWORD
nonn
AUTHOR
EXTENSIONS
Edited by N. J. A. Sloane, Jun 23 2009
Corrected (65 replaced by 66) by R. J. Mathar, May 21 2010
STATUS
approved