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 A238332 Primes whose digits, after the first, form a nonprime number not occurring earlier. 2

%I

%S 11,19,127,139,149,151,157,163,181,191,193,199,233,269,277,421,487,

%T 1117,1123,1129,1153,1171,1187,1201,1213,1217,1231,1237,1249,1259,

%U 1279,1289,1291,1297,1301,1303,1319,1321,1327,1361,1381,1399,1423,1427,1429,1447

%N Primes whose digits, after the first, form a nonprime number not occurring earlier.

%C The corresponding nonprime numbers are in A238333.

%H T. D. Noe and Reinhard Zumkeller, <a href="/A238332/b238332.txt">Table of n, a(n) for n = 1..10000</a>, first 2700 terms from T. D. Noe

%t 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]]]; t

%o a238332 n = a238332_list !! (n-1)

%o a238332_list = f [] \$ drop 4 a000040_list where

%o f xs (p:ps) | a010051 t == 1 || t `elem` xs = f xs ps

%o | otherwise = p : f (t:xs) ps

%o where t = read \$ tail \$ show p

%o -- _Reinhard Zumkeller_, Feb 28 2014

%Y Cf. A000040 (prime numbers), A238333.

%Y Cf. A010051.

%K nonn,base

%O 1,1

%A _T. D. Noe_, Feb 28 2014

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Last modified July 20 15:59 EDT 2019. Contains 325185 sequences. (Running on oeis4.)