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A064214
Least k such that k*5^n +/- 1 are twin primes.
4
4, 6, 6, 24, 42, 42, 18, 198, 42, 54, 96, 84, 522, 240, 48, 228, 708, 732, 660, 132, 528, 390, 78, 1014, 504, 1008, 1134, 504, 708, 582, 894, 516, 2982, 810, 162, 1746, 4758, 1848, 414, 4512, 2928, 1722, 4392, 1104, 1134, 1950, 390, 78, 1500, 300, 60
OFFSET
0,1
MATHEMATICA
Do[ k = 1; While[ ! PrimeQ[ k*5^n + 1 ] || ! PrimeQ[ k*5^n - 1 ], k++ ]; Print[ k ], {n, 0, 50} ]
CROSSREFS
Cf. A063983.
Sequence in context: A019090 A145692 A295512 * A019203 A365084 A082237
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Sep 21 2001
EXTENSIONS
Offset corrected by Georg Fischer, May 01 2022
STATUS
approved