A075241 Least base for which the n-th prime has no prime reversal in that base.

2, 3, 5, 7, 4, 6, 3, 2, 6, 3, 7, 4, 4, 3, 4, 5, 2, 7, 10, 3, 3, 2, 6, 2, 3, 6, 2, 3, 2, 4, 4, 4, 2, 2, 2, 4, 2, 4, 4, 4, 2, 4, 2, 10, 3, 3, 2, 3, 4, 3, 9, 2, 2, 3, 3, 4, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 4, 3, 2, 4, 6, 4, 2, 3, 2, 3, 2, 2, 2, 5, 2, 4, 4, 3, 2, 3, 6, 2, 3, 4, 2, 3, 3, 6, 2, 4, 3, 4, 2, 2, 2, 2, 2

Offset: 1

Author

Robert G. Wilson v, Sep 09 2002

Keywords

• base
• easy
• nonn

Comments

a(n) is always less than or equal to n-th prime and once past a(6) it is always less than n.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A075240, A075242.

Programs

Mathematica

a = {}; Do[k = 2; p = Prime[n]; While[ PrimeQ[ FromDigits[ Reverse[ IntegerDigits[p, k]], k]], k++ ]; a = Append[a, k], {n, 1, 105}]; a