A163488 - OEIS

%I #5 Jan 02 2018 19:31:48

%S 2,3,47,79,113,197,227,257,263,317,347,383,431,443,491,499,541,557,

%T 617,757,811,887,929,977,1021,1087,1093,1129,1231,1237,1433,1511,2111,

%U 2129,2213,2347,2543,2551,2609,2657,2671,2803,2837,2999,3011,3049,3119,3187

%N Primes p such that 5*p is a sum of 3 consecutive primes.

%C Primes of the form A034961(k)/5, associated with k=1, 2, 21, 31, 42, 66,... - R. J. Mathar, Aug 02 2009

%e p=2 is in the sequence because 2*5=10=2+3+5.

%e p=3 is in the sequence because 3*5=15=3+5+7.

%t lst={};Do[If[PrimeQ[p=(Prime[n]+Prime[n+1]+Prime[n+2])/5],AppendTo[lst, p]],{n,7!}];lst

%t cp3Q[n_]:=Module[{mid=Floor[PrimePi[(5n)/3]],tst},tst=Total/@ Partition[ Prime[ Range[mid-10,mid+10]],3,1];MemberQ[tst,5n]]; Select[ Prime[ Range[ 500]],cp3Q]//Quiet (* _Harvey P. Dale_, Jan 02 2018 *)

%Y Cf. A006562, A118134, A163487.

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, Jul 28 2009

%E Entries checked by _R. J. Mathar_, Aug 02 2009