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 A064938 Nonprimes k such that k divides prime(k)^2 - 1. 1
 1, 4, 6, 8, 10, 12, 14, 20, 24, 42, 48, 60, 63, 70, 72, 80, 84, 108, 120, 124, 126, 153, 156, 182, 240, 246, 264, 286, 327, 372, 374, 440, 492, 516, 552, 1008, 1053, 1664, 1941, 2160, 2494, 3048, 3741, 4116, 4136, 4144, 4152, 5106, 5698, 6012, 6458, 6459 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Harry J. Smith, Table of n, a(n) for n = 1..160 MATHEMATICA Select[ Range[10^4], !PrimeQ[ # ] && GCD[ #, Prime[ # ]^2 - 1] == # & ] PROG (PARI) { default(primelimit, 4294965247); n=0; for (m=1, 10^9, if (isprime(m), next); if (gcd(m, prime(m)^2 - 1) == m, write("b064938.txt", n++, " ", m); if (n==160, return)) ) } \\ Harry J. Smith, Sep 30 2009 CROSSREFS Cf. A064830. Sequence in context: A242396 A061344 A066664 * A050990 A289425 A225514 Adjacent sequences: A064935 A064936 A064937 * A064939 A064940 A064941 KEYWORD easy,nonn AUTHOR Robert G. Wilson v, Oct 26 2001 STATUS approved

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Last modified May 23 17:39 EDT 2024. Contains 372765 sequences. (Running on oeis4.)