A238333 The nonprime numbers formed from the primes in A238332.

1, 9, 27, 39, 49, 51, 57, 63, 81, 91, 93, 99, 33, 69, 77, 21, 87, 117, 123, 129, 153, 171, 187, 201, 213, 217, 231, 237, 249, 259, 279, 289, 291, 297, 301, 303, 319, 321, 327, 361, 381, 399, 423, 427, 429, 447, 451, 453, 459, 471, 481, 483, 489, 493, 511

Offset

1,2

Links

T. D. Noe, Table of n, a(n) for n = 1..2700

Mathematica

t = {}; eList = {}; p = 7; While[Length[t] < 1000, p = NextPrime[p]; e = FromDigits[Rest[IntegerDigits[p]]]; If[! PrimeQ[e] && ! MemberQ[eList, e], AppendTo[t, p]; AppendTo[eList, e]]]; eList

Prog

(Haskell)
a238333 n = a238333_list !! (n-1)
a238333_list = f [] $ drop 4 a000040_list where
   f xs (p:ps) | a010051 t == 1 || t `elem` xs = f xs ps
               | otherwise = t : f (t:xs) ps
               where t = read $ tail $ show p
-- Reinhard Zumkeller, Feb 28 2014

Crossrefs

Cf. A000040 (prime numbers), A238332.

Cf. A010051.

Sequence in context: A353238 A116455 A103753 * A103965 A069069 A354815

Adjacent sequences: A238330 A238331 A238332 * A238334 A238335 A238336

Keyword

nonn,base

Author

T. D. Noe, Feb 28 2014

Status

approved