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URL: https://oeis.org/A252020

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A252020
Odd perfect powers n not congruent to 1 mod 6 such that n*4^k - 1 has a covering set.
0
56169, 651249, 20985561, 1054235961, 1688470281, 3718682361, 3923393769, 4013349201, 5866487649, 6557598441, 7121165769, 7232992209, 8527229649, 8764891641, 9387865881, 10441365489, 12922915041, 15279184881, 17063935641, 19501284609, 19760206041
OFFSET
1,1
COMMENTS
If a(n) is a square, then for all k >= 1 the numbers a(n)*4^k - 1 have at least three distinct prime factors.
CROSSREFS
Sequence in context: A022224 A230336 A252320 * A360188 A031655 A203964
KEYWORD
nonn
AUTHOR
STATUS
approved