A038532 Primes that are concatenations of k-th composite and k-th prime.

97, 1213, 2137, 2861, 3067, 3271, 3373, 3583, 48131, 55163, 56167, 57173, 62191, 70229, 86293, 90313, 93337, 96353, 99367, 104383, 105389, 106397, 108401, 117443, 123479, 126499, 129509, 132523, 133541, 138569, 143593, 145601

Offset

1,1

Links

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

Mathematica

nn=250; Module[{prs=Prime[Range[nn]], comps, concats}, comps=Take[Complement[ Range[2, Prime[nn]+1], prs], nn]; concats=FromDigits[Flatten[ IntegerDigits/@#]]&/@ Thread[{comps, prs}]; Select[concats, PrimeQ]] (* Harvey P. Dale, Apr 27 2012 *)

Crossrefs

Cf. A038531.

Sequence in context: A087596 A133836 A224106 * A226082 A092272 A233433

Adjacent sequences: A038529 A038530 A038531 * A038533 A038534 A038535

Keyword

nonn,base

Author

Vasiliy Danilov (danilovv(AT)usa.net), Jul 14 1998

Extensions

Edited by Charles R Greathouse IV, Apr 23 2010

Status

approved