A120745 - OEIS

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, 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

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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