A248208 Primes p such that p^3 is the concatenation of two k-digit primes where k is half the number of decimal digits in p^3.

3, 11, 47, 83, 1063, 1637, 1699, 7529, 7673, 23059, 28097, 29573, 34157, 34961, 36587, 40897, 43609, 44711, 101839, 102763, 103423, 104087, 104393, 106363, 117437, 117499, 124471, 125407, 126011, 129419, 134753, 135007, 137393, 139487, 143879, 143971, 145037

Offset

1,1

Links

Jens Kruse Andersen, Table of n, a(n) for n = 1..10000

Example

47 is prime and 47^3 = 103823 is the concatenation of two primes (103 and 823) that are of the same length (here, their length is 3). So, 47 is a member of this sequence.
73 is not in the sequence since 73^3 = 389017, where 389 is a 3-digit prime but 017 is a 2-digit prime. - Jens Kruse Andersen, Oct 06 2014

Prog

(PARI)
forprime(p=1, 10^6, d=digits(p^3); if((#d)%2==0, if(isprime((p^3)\(10^(#d/2)))&&isprime((p^3)%(10^(#d/2)))&&#Str((p^3)%(10^(#d/2)))==#d/2, print1(p, ", "))))

Crossrefs

Cf. A030078, A105184, A030461, A153048, A080906, A248046.

Sequence in context: A030976 A264416 A290712 * A112567 A163063 A151142

Adjacent sequences: A248205 A248206 A248207 * A248209 A248210 A248211

Keyword

nonn,base

Author

Derek Orr, Oct 03 2014

Extensions

Terms and PARI program corrected by Jens Kruse Andersen, Oct 06 2014

Status

approved