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 A108510 Primes p such that 3^A000027*(7*p) is a subsequence of A033631. 1
 1979, 2699, 7649, 1131569, 2482199, 2886839, 90425537, 2774476799 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS There is no further term up to prime(300000000). LINKS Table of n, a(n) for n=1..8. EXAMPLE Let n be a natural number and m=3^n*7*90425537; then sigma(phi(m)) = sigma(3^(n-1)*2*6*90425536) = sigma(3^n*2^8*677*2087) = sigma(3^n)*8*90425538 = sigma(3^n)*sigma(7)*sigma(90425537) = sigma(3^n*7*90425537) = sigma(m), hence m is in A033631 and the prime number 90425537 is a term of this sequence. CROSSREFS Cf. A000027, A033631. Sequence in context: A205364 A210160 A234179 * A343971 A343972 A225235 Adjacent sequences: A108507 A108508 A108509 * A108511 A108512 A108513 KEYWORD more,nonn AUTHOR Farideh Firoozbakht, Jun 07 2005 STATUS approved

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Last modified March 2 21:08 EST 2024. Contains 370498 sequences. (Running on oeis4.)