A256353 Composites in base 10 that remain composite in exactly five bases b, 2 <= b <= 10, expansions interpreted as decimal numbers.

55, 169, 247, 253, 323, 493, 529, 556, 671, 1027, 1111, 1243, 1261, 1339, 1375, 1711, 1751, 1803, 2185, 2413, 2431, 2881, 3193, 4381, 4417, 4843, 5029, 5203, 5251, 6631, 7093, 7999, 8515, 8653, 9271, 9307, 9481, 9523, 9593, 9727, 9745, 9937, 9955, 10393, 10555

Offset: 1

Author

Sebastian Petzelberger, Mar 25 2015

Keywords

• nonn
• base

Comments

Less remaining is not possible for even numbers.

Links

• Sebastian Petzelberger, Table of n, a(n) for n = 1..10000
• Carlos Rivera, PP&P Puzzle 24: Primes in several bases

Crossrefs

Cf. A052026, A256350-A256356, A038537, A052027-A052033, A084482, A236356.