A319042 Composite numbers k such that Pell(k) == 1 (mod k).

35, 169, 385, 899, 961, 1121, 2001, 3107, 4879, 4901, 5719, 6215, 6265, 6441, 6479, 6601, 7055, 7801, 8119, 8339, 9799, 10403, 10763, 10945, 13079, 13601, 15841, 18241, 19097, 20833, 20951, 22499, 24727, 27839, 29183, 29953, 30731, 31417, 31535, 34561, 37345

Offset

1,1

Comments

It appears that most of the terms of A319040 (Numbers k such that Pell(k) == 1 (mod k)) are primes; this sequence lists the composites.

For the composite numbers k such that Pell(k) == -1 (mod k), see A319043.

Links

Seiichi Manyama, Table of n, a(n) for n = 1..500

Example

k=35 is in the sequence: Pell(35) = 8822750406821 = 35*252078583052 + 1 == 1 (mod 35).
k=6 is not in the sequence: Pell(6) = 70 = 6*12 - 2 !== 1 (mod 6).

Crossrefs

Cf. A000129 (Pell numbers), A094394, A319040, A319041, A319043.

Sequence in context: A270860 A228453 A327651 * A033851 A219825 A194716

Adjacent sequences: A319039 A319040 A319041 * A319043 A319044 A319045

Keyword

nonn

Author

Jon E. Schoenfield, Sep 08 2018

Status

approved