A220953 Primes p such that floor(sqrt(2)) + floor(sqrt(3)) + floor(sqrt(5)) + ... + floor(sqrt(p)) is prime.

3, 29, 61, 73, 127, 181, 229, 251, 281, 313, 367, 487, 503, 509, 547, 587, 599, 601, 613, 617, 659, 727, 739, 751, 797, 809, 829, 863, 881, 983, 1033, 1061, 1087, 1103, 1153, 1163, 1223, 1277, 1381, 1861, 1871, 2039, 2063, 2099, 2113, 2131, 2203, 2221

Offset: 1

Author

Daniel J. Hardisky, Feb 20 2013

Keywords

• nonn

Links

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

Crossrefs

Cf. A062048.

Programs

Magma

[NthPrime(i): i in [1..400] | IsPrime(S) where S is &+[Floor(Sqrt(NthPrime(k))): k in [1..i]]]; // Bruno Berselli, Feb 21 2013

Mathematica

ps = Prime[Range[1000]]; t = {}; s = 0; Do[s = s + Floor[Sqrt[p]]; If[PrimeQ[s], AppendTo[t, p]], {p, ps}]; t (* T. D. Noe, Feb 21 2013 *)

PARI

s=0;forprime(p=2,1e4,if(isprime(s+=sqrtint(p)),print1(p", "))) \\ Charles R Greathouse IV, Feb 21 2013