A084409 Main diagonal of triangle A084408.

1, 3, 11, 9, 29, 18, 59, 28, 40, 54, 107, 69, 179, 87, 106, 125, 271, 147, 389, 172, 200, 224, 541, 254, 286, 316, 346, 381, 727, 416, 941, 455, 495, 534, 575, 620, 1201, 665, 710, 756, 1493, 804, 1823, 856, 909, 962, 2203, 1018, 1077, 1136, 1194, 1254, 2621

Offset

1,2

Comments

a(n) is prime iff n is prime.

Links

Table of n, a(n) for n=1..53.

Formula

For n prime, a(n) = p(A034387(n)). For n composite, a(n) = A002808([n*(n+1)/2]-A034387(n)-1).

Crossrefs

Cf. A084408, A084410, A084411.

Sequence in context: A205120 A070613 A316884 * A038229 A257538 A304052

Adjacent sequences: A084406 A084407 A084408 * A084410 A084411 A084412

Keyword

nonn,easy

Author

Amarnath Murthy, Jun 01 2003

Extensions

Edited and extended by David Wasserman, Dec 27 2004

Status

approved