id:A163368 - OEIS Search Results

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phi(sigma(tau(n)))

+0
1

1, 2, 2, 2, 2, 6, 2, 6, 2, 6, 2, 4, 2, 6, 6, 2, 2, 4, 2, 4, 6, 6, 2, 8, 2, 6, 6, 4, 2, 8, 2, 4, 6, 6, 6, 12, 2, 6, 6, 8, 2, 8, 2, 4, 4, 6, 2, 6, 2, 4 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`a(n) = A000010(A000203(A000005(n))) = A000010(A062069(n)) = A062401(A000005(n)).`
	FORMULA	`a(1) = 1, a(p) = 2 for p = primes (A000040), a(pq) = 6 for pq = product of two distinct primes (A006881), a(pq...z) = A000010(2^(k+1)-1) = A053287(k+1) for pq...z = product of k (k > 2) distinct primes p,q,...,z (A120944).`
	CROSSREFS	`Sequence in context: A156717 A130754 A164126 this_sequence A151948 A080400 A119462` `Adjacent sequences: A163365 A163366 A163367 this_sequence A163369 A163370 A163371`
	KEYWORD	`nonn`
	AUTHOR	`Jaroslav Krizek (jaroslav.krizek(AT)atlas.cz), Jul 25 2009`

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Last modified November 24 19:42 EST 2009. Contains 167435 sequences.

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