A167716 Squares that become a prime number when prefixed with a 1.

1, 9, 49, 81, 289, 361, 1369, 1681, 2401, 2601, 2809, 3249, 3721, 4489, 5329, 6561, 6889, 7569, 7921, 9801, 10609, 14161, 14641, 19321, 19881, 21609, 22201, 25921, 32761, 35721, 36481, 40401, 41209, 47089, 49729, 52441, 61009, 67081, 77841

Offset: 1

Author

Claudio Meller, Nov 10 2009

Keywords

• base
• nonn

Comments

Subsequence of squares of A032664. - Michel Marcus, Jun 21 2016

Links

• G. C. Greubel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A032664.

Programs

Mathematica

Select[Range[1, 700, 2]^2, PrimeQ[FromDigits[Join[{1}, IntegerDigits[#]]]] &] (* G. C. Greubel, Jun 21 2016 *)
Select[Range[1,701,2]^2,PrimeQ[10^IntegerLength[#]+#]&] (* Harvey P. Dale, Mar 31 2019 *)