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A238333 The nonprime numbers formed from the primes in A238332. 2
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 (list; graph; refs; listen; history; text; internal format)
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: A036303 A116455 A103753 * A103965 A069069 A031088

Adjacent sequences:  A238330 A238331 A238332 * A238334 A238335 A238336

KEYWORD

nonn,base

AUTHOR

T. D. Noe, Feb 28 2014

STATUS

approved

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Last modified June 25 12:01 EDT 2019. Contains 324352 sequences. (Running on oeis4.)