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 A084409 Main diagonal of triangle A084408. 3
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(n) is prime iff n is prime. LINKS 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

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Last modified October 23 20:14 EDT 2019. Contains 328373 sequences. (Running on oeis4.)