A163561 Composite numbers such that exactly nine distinct permutations of digits give primes.

1094, 1349, 1394, 1457, 1475, 1490, 1547, 1574, 1745, 1754, 1904, 1934, 1940, 1943, 3097, 3149, 3194, 3419, 3479, 3497, 3679, 3749, 3790, 3794, 3796, 3914, 3941, 3970, 3974, 3976, 4109, 4175, 4190, 4193, 4319, 4379, 4571, 4715, 4739, 4901, 4910, 4913

Offset

1,1

Links

Table of n, a(n) for n=1..42.

Example

a(1) = 1094 because 1094 is composite, the nine permutations 149, 419, 491, 941, 1049, 1409, 4019, 4091, and 9041 are all prime, and no other permutation of 1094 is prime.

Crossrefs

Sequence in context: A022197 A259909 A124122 * A203807 A184470 A234722

Adjacent sequences: A163558 A163559 A163560 * A163562 A163563 A163564

Keyword

easy,nonn,base

Author

Gil Broussard, Jul 30 2009

Status

approved