A161777 n-th nonprime*(n-th nonprime-1)/2

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

Links

Table of n, a(n) for n=1..50.

Formula

a(n) = A000217(A018252(n)-1). [From R. J. Mathar, May 21 2010]

Crossrefs

Cf. A000217, A018252.

Sequence in context: A335267 A349476 A242454 * A117519 A091012 A241988

Adjacent sequences: A161774 A161775 A161776 * A161778 A161779 A161780

Keyword

nonn

Author

Juri-Stepan Gerasimov, Jun 19 2009

Extensions

Edited by N. J. A. Sloane, Jun 23 2009

Corrected (65 replaced by 66) by R. J. Mathar, May 21 2010

Status

approved