A246503 Numbers m such that m^2 divides 2^k - 1 for some k, 0 < k <= m.

1, 1093, 3279, 3511, 5465, 7651, 9837, 10533, 14209, 16395, 17555, 18581, 22953, 24577, 31599, 31697, 38255, 38621, 42627, 45643, 46999, 49185, 52665, 53557, 55743, 57929, 60115, 62301, 66709, 68859, 71045, 73731, 84161, 86347, 92905, 94797, 95091, 99463

Offset

1,2

Comments

All terms are odd. m=1 is the only term with k=m.

Odd numbers m such that A007733(m^2) = A002326((m^2-1)/2) <= m.

Prime terms are Wieferich primes (A001220).

Links

Chai Wah Wu, Table of n, a(n) for n = 1..127

Prog

(Python)
A246503_list = [1]
for i in range(2, 10**4):
....d, n = i*i, 1
....for _ in range(i):
........n = (2*n) % d
........if n == 1:
............A246503_list.append(i)
............break # Chai Wah Wu, Dec 04 2014

Crossrefs

Cf. A001220, A002326.

Sequence in context: A252520 A023698 A038469 * A077816 A291961 A001220

Adjacent sequences: A246500 A246501 A246502 * A246504 A246505 A246506

Keyword

nonn

Author

Max Alekseyev, Nov 29 2014

Status

approved