A264611 Consider pairs of primes p<q such that p|q^2 + q + 1 and q|p^2 + p + 1; sequence gives p values.

3, 13, 22419767768701

Offset

1,1

Links

Table of n, a(n) for n=1..3.

T. Cai, Z. Shen, L. Jia, A congruence involving harmonic sums modulo p^alpha q^beta, arXiv preprint arXiv:1503.02798 [math.NT], 2015.

Yong-Gao Chen, and Xin Tong, On a conjecture of de Koninck, Journal of Number Theory, Volume 154, September 2015, Pages 324-364. See Remark 2 p. 331.

Example

The known pairs are (3, 13),(13, 61),(22419767768701, 107419560853453).

Crossrefs

Cf. A264612.

Sequence in context: A087345 A048756 A174211 * A157323 A016549 A147584

Adjacent sequences: A264608 A264609 A264610 * A264612 A264613 A264614

Keyword

nonn,more

Author

N. J. A. Sloane, Nov 25 2015

Status

approved