A086455 - OEIS

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A086455

Sum of divisors of prime powers: sigma(p^e).

1, 3, 4, 7, 6, 8, 15, 13, 12, 14, 31, 18, 20, 24, 31, 40, 30, 32, 63, 38, 42, 44, 48, 57, 54, 60, 62, 127, 68, 72, 74, 80, 121, 84, 90, 98, 102, 104, 108, 110, 114, 133, 156, 128, 255, 132, 138, 140, 150, 152, 158, 164, 168, 183, 174, 180, 182, 192, 194, 198 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`a(n) = A000203(A000961(n)).`
	LINKS	`Eric Weisstein's World of Mathematics, Prime Power.` `Eric Weisstein's World of Mathematics, Divisor Function`
	FORMULA	`a(p^e) = (p^(e+1)-1)/(p-1): a(n)=(A025473(n)^(A025474(n)+1)-1)/(A025473(n)-1).`
	CROSSREFS	`Cf. A086454.` `Sequence in context: A120224 A183107 A132009 * A204823 A096842 A147966` `Adjacent sequences: A086452 A086453 A086454 * A086456 A086457 A086458`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jul 20 2003`

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Last modified February 17 13:28 EST 2012. Contains 206031 sequences.