id:A053158 - OEIS Search Results

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Sum of n and its cototient function value (A051953).

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1, 3, 4, 6, 6, 10, 8, 12, 12, 16, 12, 20, 14, 22, 22, 24, 18, 30, 20, 32, 30, 34, 24, 40, 30, 40, 36, 44, 30, 52, 32, 48, 46, 52, 46, 60, 38, 58, 54, 64, 42, 72, 44, 68, 66, 70, 48, 80, 56, 80, 70, 80, 54, 90, 70, 88, 78, 88, 60, 104, 62, 94, 90, 96, 82, 112, 68, 104, 94, 116 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`For Mersenne primes and also for certain composites the values of this function are powers of 2.`
	FORMULA	`a(n)=n+A051953(n)=2n-EulerPhi(n)`
	EXAMPLE	`n=127, a(127)=254-126=128 n=80, a(80)=160-32=128 n=2^s, a(2^s)=3*2^(s-1)`
	CROSSREFS	`A000043, A000668, A001368, A051953.` `Sequence in context: A158907 A023830 A063649 this_sequence A158523 A001615 A133689` `Adjacent sequences: A053155 A053156 A053157 this_sequence A053159 A053160 A053161`
	KEYWORD	`nonn`
	AUTHOR	`Labos E. (labos(AT)ana.sote.hu), Feb 29 2000`

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

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