A246400 Smallest prime Q greater than prime(n+1) such that the sum prime(n)+prime(n+1)+Q is also prime, starting with n=2.

11, 11, 13, 17, 23, 23, 29, 31, 37, 41, 53, 47, 59, 67, 61, 71, 71, 73, 79, 89, 89, 97, 107, 109, 107, 127, 131, 127, 139, 139, 151, 157, 151, 157, 179, 167, 173, 181, 211, 197, 197, 223, 211, 211, 233, 227, 233, 263, 239, 271, 263, 269, 313, 277, 277, 281, 281

Offset

2,1

Comments

The sequence A152470 is a subsequence.

Links

Pierre CAMI, Table of n, a(n) for n = 2..10001

Example

3+5+7=15 is composite and 3+5+11=19 is prime so a(2)=11.
5+7+11=23 is prime so a(3)=11.

Mathematica

spq[n_]:=Module[{m=NextPrime[n], q}, q=NextPrime[m]; While[!PrimeQ[ m+n+q], q=NextPrime[q]]; q]; Table[spq[n], {n, Prime[Range[2, 60]]}] (* Harvey P. Dale, Apr 08 2018 *)

Prog

(PFGW & SCRIPT)
SCRIPT
DIM k
DIM n, 1
OPENFILEOUT myf, a(n).txt
LABEL loop1
SET n, n+1
IF n>10001 THEN END
SET k, n+1
LABEL loop2
SET k, k+1
PRP p(n)+p(n+1)+p(k)
IF ISPRP then GOTO a
GOTO loop2
LABEL a
WRITE myf, p(k)
GOTO loop1
(PARI) a(n) = t=prime(n)+prime(n+1); k=n+2; while(!isprime(t+q=prime(k)), k++); q \\ Colin Barker, Aug 25 2014

Crossrefs

Cf. A152470.

Sequence in context: A134036 A110415 A052257 * A180022 A003856 A167130

Adjacent sequences: A246397 A246398 A246399 * A246401 A246402 A246403

Keyword

nonn

Author

Pierre CAMI, Aug 25 2014

Status

approved