A179632 Primes p such that p + the integer part of square root of its digits is a prime.

2, 5, 11, 19, 67, 101, 109, 127, 163, 457, 557, 587, 593, 599, 613, 647, 677, 823, 857, 877, 941, 971, 1009, 1097, 1187, 1213, 1277, 1291, 1367, 1427, 1453, 1481, 1483, 1543, 1553, 1559, 1663, 1741, 1753, 1783, 1861, 1871, 1873, 1907, 2083, 2267, 2287, 2377, 2393, 2417, 2441, 2459

Offset

1,1

Links

Paolo Xausa, Table of n, a(n) for n = 1..10000

Example

67 is in the sequence since 67 + floor(sqrt(6)) + floor(sqrt(7)) = 67+2+2 = 71 is prime.

Mathematica

Select[Prime[Range[500]], PrimeQ[# + Total[Floor[Sqrt[IntegerDigits[#]]]]] &] (* Paolo Xausa, Jan 13 2026 *)

Prog

(PARI) isok(n) = {if (isprime(n), digs = digits(n, 10); isprime(n + sum(i=1, #digs, sqrtint(digs[i]))); , 0; ); } \\ Michel Marcus, Jul 18 2013

Crossrefs

Cf. A179633.

Sequence in context: A051653 A106015 A178316 * A093871 A139482 A038377

Adjacent sequences: A179629 A179630 A179631 * A179633 A179634 A179635

Keyword

nonn,base

Author

Carmine Suriano, Jul 21 2010

Extensions

More terms from Paolo Xausa, Jan 13 2026

Status

approved