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 A025476 Prime root of n-th nontrivial prime power (A025475, A246547). 4
 2, 2, 3, 2, 5, 3, 2, 7, 2, 3, 11, 5, 2, 13, 3, 2, 17, 7, 19, 2, 23, 5, 3, 29, 31, 2, 11, 37, 41, 43, 2, 3, 13, 47, 7, 53, 5, 59, 61, 2, 67, 17, 71, 73, 79, 3, 19, 83, 89, 2, 97, 101, 103, 107, 109, 23, 113, 11, 5, 127, 2, 7, 131, 137, 139, 3, 149, 151, 29, 157, 163, 167, 13, 31, 173, 179 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..76. MAPLE cvm := proc(n, level) local f, opf; if n < 2 then RETURN() fi; f := ifactors(n); opf := op(1, op(2, f)); if nops(op(2, f)) > 1 or op(2, opf) <= level then RETURN() fi; op(1, opf) end: A025476_list := n -> seq(cvm(i, 1), i=1..n); # n is search limit A025476_list(30000); # Peter Luschny, Sep 21 2011 # Alternative: isA246547 := n -> n > 1 and not isprime(n) and type(n, 'primepower'): seq(ifactors(p)[2][1][1], p in select(isA246547, [\$1..30000])); # Peter Luschny, Jul 15 2023 MATHEMATICA Transpose[ Flatten[ FactorInteger[ Select[ Range[2, 30000], !PrimeQ[ # ] && Mod[ #, # - EulerPhi[ # ]] == 0 &]], 1]][[1]] (* Robert G. Wilson v *) PROG (PARI) forcomposite(n=4, 10^5, if( ispower(n, , &p) && isprime(p), print1(p, ", "))) \\ Joerg Arndt, Sep 11 2021 CROSSREFS Cf. A025473, A025475, A048148, A246547. Sequence in context: A157987 A025478 A084371 * A347731 A331532 A078773 Adjacent sequences: A025473 A025474 A025475 * A025477 A025478 A025479 KEYWORD easy,nonn AUTHOR David W. Wilson STATUS approved

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Last modified December 2 07:10 EST 2023. Contains 367510 sequences. (Running on oeis4.)