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A084410 First column of triangle A084408. 3
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 (list; graph; refs; listen; history; text; internal format)
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 * A080067 A117824 A122212

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

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Last modified July 20 16:15 EDT 2019. Contains 325185 sequences. (Running on oeis4.)