A210242 Pairs of consecutive primes {p,q} for which the numbers of distinct residues of all factorials mod p and mod q coincide.

17, 19, 89, 97, 137, 139, 263, 269, 757, 761, 907, 911, 1201, 1213, 1481, 1483, 2309, 2311, 2609, 2617, 4679, 4691, 5743, 5749, 10733, 10739, 16103, 16111, 16267, 16273, 19759, 19763, 20269, 20287, 32531, 32533, 35509, 35521, 38693, 38699, 42499, 42509, 43633, 43649

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..240

Formula

pi(a(2*n)) = pi(a(2*n-1)) + 1.

A210184(pi(a(2*n))) = A210184(pi(a(2*n-1))).

Mathematica

t = {}; last = 2; Do[new = Length[Union[Mod[Range[Prime[n]]!, Prime[n]]]]; If[last == new, AppendTo[t, {Prime[n - 1], Prime[n]}]]; last = new, {n, 2, 100}]; t (* T. D. Noe, Mar 20 2012 *)

Crossrefs

Cf. A210184, A210336.

Sequence in context: A180559 A272478 A028489 * A165320 A132242 A162873

Adjacent sequences: A210239 A210240 A210241 * A210243 A210244 A210245

Keyword

nonn,tabf

Author

Vladimir Shevelev, Mar 19 2012

Extensions

More terms from Amiram Eldar, Sep 14 2019

Status

approved