A084410 First column of triangle A084408.

1, 2, 5, 4, 13, 10, 31, 20, 30, 42, 61, 55, 109, 70, 88, 108, 181, 126, 277, 148, 174, 201, 397, 225, 255, 287, 318, 348, 547, 382, 733, 417, 456, 496, 535, 576, 947, 621, 666, 711, 1213, 758, 1499, 805, 858, 910, 1831, 963, 1020, 1078, 1137, 1195, 2207, 1255

Offset

1,2

Comments

a(n) is prime iff n is prime.

Links

Table of n, a(n) for n=1..54.

Formula

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

Crossrefs

Cf. A084408, A084409, A084411.

Sequence in context: A111681 A073122 A277020 * A338073 A080067 A117824

Adjacent sequences: A084407 A084408 A084409 * A084411 A084412 A084413

Keyword

nonn,easy

Author

Amarnath Murthy, Jun 01 2003

Extensions

Edited and extended by David Wasserman, Dec 27 2004

Status

approved