A023897 - OEIS

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A023897

sigma_1(n) / phi(n) for balanced numbers.

1, 3, 2, 6, 7, 4, 3, 9, 2, 8, 5, 6, 7, 4, 7, 10, 5, 12, 4, 9, 10, 3, 4, 14, 10, 8, 6, 13, 9, 8, 5, 15, 7, 2, 6, 8, 4, 5, 12, 6, 7, 10, 10, 11, 14, 12, 9, 4, 3, 4, 12, 9, 4, 4, 7, 5, 7, 10, 3, 5, 4, 13, 14, 12, 10, 9, 10, 8, 7, 4, 8, 6, 18, 9, 3, 8, 13, 8, 15, 15, 8, 3, 14, 9, 10, 8, 8, 10, 5, 7, 8, 11, 6, 11, 13, 6 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`sigma_1(n) is the sum of the divisors of n [same as sigma(n)] (A000203).`
	MATHEMATICA	`Select[ Array[ DivisorSigma[ 1, # ]/EulerPhi[ # ]&, 20000 ], IntegerQ ]`
	PROG	`(MAGMA) [ q: n in [1..20000] \| r eq 0 where q, r is Quotrem(SumOfDivisors(n), EulerPhi(n)) ]; [From Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Nov 09 2008]`
	CROSSREFS	`Cf. A000010, A000203, A020492.` `Sequence in context: A102004 A196518 A125764 * A178754 A100527 A063946` `Adjacent sequences: A023894 A023895 A023896 * A023898 A023899 A023900`
	KEYWORD	`nonn`
	AUTHOR	`Olivier Gerard (olivier.gerard(AT)gmail.com)`

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Last modified February 13 10:39 EST 2012. Contains 205459 sequences.