A161540 Primes which are the sum of a smaller n and its composite(n) subscript. A002808 + a(n) (= prime)

5, 11, 13, 23, 31, 67, 73, 97, 107, 109, 113, 137, 139, 157, 163, 167, 197, 199, 211, 233, 239, 251, 257, 269, 271, 293, 307, 311, 313, 331, 337, 347, 353, 359, 367, 373, 401, 409, 449, 457, 479, 487, 491, 503, 541, 547, 569, 571, 577, 587, 593, 607, 613, 617

Offset

1,1

Comments

5 = composite(1)+1 = 4+1 ; 11 = composite(3)+3 = 8+3

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Mathematica

Module[{nn=400, cmps, len}, cmps=Select[Range[nn], CompositeQ]; len=Length[cmps]; Select[ Total/@ Thread[{Range[len], cmps}], PrimeQ]] (* Harvey P. Dale, Jul 07 2024 *)

Crossrefs

A002808

Sequence in context: A190620 A079732 A309158 * A153120 A115782 A051654

Adjacent sequences: A161537 A161538 A161539 * A161541 A161542 A161543

Keyword

nonn

Author

Claudio Meller, Jun 13 2009

Status

approved