A166503 Numbers k with property that k^2 is the concatenation of two or more prime numbers.

5, 15, 17, 19, 23, 27, 49, 51, 53, 69, 73, 77, 85, 87, 107, 109, 115, 123, 141, 147, 151, 153, 157, 159, 163, 165, 171, 173, 177, 181, 187, 191, 199, 219, 229, 231, 233, 235, 239, 241, 243, 267, 269, 277, 279, 281, 289, 299, 319, 327, 331, 335, 337, 343, 357

Offset: 1

Author

Zak Seidov, Oct 15 2009

Keywords

• nonn
• base

Comments

Only odd numbers are eligible.

Links

• Jinyuan Wang, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A019549, A038692, A105184, A129800.

Programs

PARI

for(n=1, 9999, is_A152242(n^2) & print1(n, ", ")) \\ M. F. Hasler, Oct 15 2009

Formula

a(n) = sqrt(A038692(n)).

Extensions

Terms updated according to stricter definition of A152242 by M. F. Hasler, Oct 15 2009