A117738 Least number d such that 10^n -/+ 3d form a prime pair.

1, 1, 3, 23, 43, 13, 87, 71, 153, 11, 19, 13, 89, 219, 119, 459, 1, 129, 633, 131, 71, 217, 1091, 911, 1141, 511, 143, 201, 377, 379, 371, 377, 83, 201, 993, 53, 143, 307, 423, 919, 259, 263, 759, 3933, 3, 1781, 607, 2327, 7683, 541, 3443, 6507, 4023, 3399, 899

Offset

1,3

Links

Table of n, a(n) for n=1..55.

Formula

A115564(n)/3.

Mathematica

f[n_] := Block[{k = 1}, While[ ! PrimeQ[10^n - 3k] || ! PrimeQ[10^n + 3k], k++ ]; k]; Array[f, 55]

Crossrefs

Sequence in context: A309935 A212396 A319976 * A014582 A146142 A105854

Adjacent sequences: A117735 A117736 A117737 * A117739 A117740 A117741

Keyword

nonn

Author

Robert G. Wilson v, Apr 12 2006

Status

approved