A108473 Numbers n such that 4*prime(n)+prime(n+1) is composite.

3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 17, 19, 20, 21, 22, 24, 25, 26, 27, 28, 29, 30, 31, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 52, 53, 54, 57, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85

Offset

1,1

Comments

Complement to A108472.

Links

Table of n, a(n) for n=1..72.

Mathematica

ra=Range[200]; cnd=!PrimeQ[4*Prime[ # ]+Prime[ #+1]]&; se=Select[ra, cnd]
Rest[Flatten[Position[4First[#]+Last[#]&/@Partition[Prime[Range[100]], 2, 1], _?(!PrimeQ[#]&)]]] (* Harvey P. Dale, Feb 18 2013 *)

Crossrefs

Cf. A108472.

Sequence in context: A191838 A333214 A363768 * A298113 A026447 A194378

Adjacent sequences: A108470 A108471 A108472 * A108474 A108475 A108476

Keyword

nonn

Author

Zak Seidov, Jun 04 2005

Status

approved