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Numbers k with property that the sum of 70 successive primes starting with prime(k) is a square.
8

%I #25 Nov 09 2022 13:28:17

%S 71,201,1024,1594,10915,36934,51050,60054,60914,71822,80331,85230,

%T 92916,96352,103271,114667,151019,158591,183484,184348,193979,196078,

%U 223587,277476,295890,309502,317601,334181,338139,369101,485330,494188,530832

%N Numbers k with property that the sum of 70 successive primes starting with prime(k) is a square.

%C Sum_{i=k..k+69} prime(i) = s^2; and the values of s are A166256.

%H David A. Corneth, <a href="/A166255/b166255.txt">Table of n, a(n) for n = 1..693</a> (first 100 terms from Zak Seidov)

%e prime(71)+...+prime(71+69) = 200^2 = A166256(1)^2,

%e prime(201)+...+prime(201+69) = 322^2 = A166256(2)^2,

%e prime(1024)+...+prime(1024+69) = 770^2 = A166256(3)^2.

%t PrimePi[First[#]]&/@Select[Partition[Prime[Range[1000000]],70,1], IntegerQ[ Sqrt[ Total[#]]]&] (* _Harvey P. Dale_, Jun 13 2011 *)

%Y Cf. A166256.

%Y Cf. A064397 (2 primes), A076305 (3 primes), A072849 (4 primes), A166261 (120 primes).

%K nonn,less

%O 1,1

%A _Zak Seidov_, Oct 10 2009