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 A071394 Numbers n divisible by pi(n) [A057809] with prime pi(n); i.e., largest prime factor of n equals pi(n). 3
 4, 6, 33, 335, 355, 3073, 8408, 64690, 481044, 1304693, 1304719, 3524318, 3524654, 9559785, 9559905, 70115803, 189963234, 189963918, 514278263, 1394194660, 3779856591, 10246935974, 75370122456, 204475052725, 204475053325, 1505578023783, 1505578024917 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Giovanni Resta, Table of n, a(n) for n = 1..49 FORMULA A000720(a(n)) = A006530(a(n)) = A256394(n). - Jonathan Sondow, Apr 15 2015 EXAMPLE pi(8408) = 1051 and 8408 = 2*2*2*1051. MATHEMATICA c = 0; lpf[n_] := If[ PrimeQ[n], c++; n, Transpose[ FactorInteger[n]][[1, -1]]]; Do[ If[ lpf[n] == c, Print[n]], {n, 2, 10^7}] Select[Select[Range[2, 10^6], IntegerQ[#/PrimePi[#]]&], PrimeQ[PrimePi[#]]&] (* Ivan N. Ianakiev, Apr 15 2015 *) Select[Range[10^6], FactorInteger[#][[-1, 1]] == PrimePi@ # &] (* Michael De Vlieger, Jul 30 2017 *) PROG (PARI) isok(n) = isprime(p=primepi(n)) && !(n % p); \\ Michel Marcus, Jul 31 2017 CROSSREFS Cf. A000720, A006530, A256394. Sequence in context: A164127 A180139 A222490 * A137021 A176002 A175061 Adjacent sequences: A071391 A071392 A071393 * A071395 A071396 A071397 KEYWORD nonn AUTHOR Jason Earls, Jun 12 2002 EXTENSIONS Edited and extended by Robert G. Wilson v, Jun 13 2002 More terms from Hans Havermann, Jul 02 2002 a(26)-a(27) from Giovanni Resta, Mar 28 2017 STATUS approved

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Last modified September 13 05:16 EDT 2024. Contains 375859 sequences. (Running on oeis4.)