

A215696


a(n)=smallest positive k>n+2 such that k*n+1 is a square.


1



8, 12, 8, 12, 16, 20, 24, 15, 32, 36, 40, 24, 48, 52, 24, 33, 64, 68, 72, 42, 40, 84, 88, 35, 96, 100, 104, 60, 112, 56, 120, 69, 56, 132, 48, 78, 144, 148, 72, 60, 160, 72, 168, 96, 91, 180, 184, 63, 192, 196, 88, 114, 208, 212, 105, 85, 104, 228, 232, 84
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OFFSET

1,1


COMMENTS

For any n and k=n+2, 1+k*n=(n+1)^2, so here we consider the case k>n+2. Cases k<n2 are considered in A076942, A215653.


LINKS

Zak Seidov, Table of n, a(n) for n = 1..1000


PROG

(PARI) for(n=1, 100, k=n+3; while(!issquare(1+k*n), k++); print1(k", "))


CROSSREFS

Cf. A076942, A215653.
Sequence in context: A014453 A160862 A152077 * A325809 A173461 A295782
Adjacent sequences: A215693 A215694 A215695 * A215697 A215698 A215699


KEYWORD

nonn


AUTHOR

Zak Seidov, Aug 21 2012


STATUS

approved



