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 A120745 a(1)=1 and, for n>1, a(n) is the smallest positive integer such that 1+S^2 is prime, where S=Sum[k, k=a(n-1)+1,...,a(n)]. 1
 1, 2, 17, 42, 57, 62, 122, 162, 177, 222, 242, 297, 442, 557, 577, 582, 637, 662, 677, 722, 757, 762, 842, 882, 897, 957, 1002, 1022, 1077, 1102, 1117, 1157, 1182, 1197, 1237, 1282, 1317, 1342, 1357, 1362, 1382, 1417, 1422, 1462, 1602, 1622, 1642, 1662 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS It appears that all differences a(n+1)-a(n), after the first, are multiples of 5. The sequence of differences is A120746. LINKS Table of n, a(n) for n=1..48. CROSSREFS Cf. A120746, A087128. Sequence in context: A186687 A256145 A096172 * A165637 A100271 A046973 Adjacent sequences: A120742 A120743 A120744 * A120746 A120747 A120748 KEYWORD nonn AUTHOR John W. Layman, Jun 30 2006 STATUS approved

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Last modified February 21 04:08 EST 2024. Contains 370219 sequences. (Running on oeis4.)