A073256 - OEIS

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A073256

EulerPhi of n-th composite number.

2, 2, 4, 6, 4, 4, 6, 8, 8, 6, 8, 12, 10, 8, 20, 12, 18, 12, 8, 16, 20, 16, 24, 12, 18, 24, 16, 12, 20, 24, 22, 16, 42, 20, 32, 24, 18, 40, 24, 36, 28, 16, 30, 36, 32, 48, 20, 32, 44, 24, 24, 36, 40, 36, 60, 24, 32, 54, 40, 24, 64, 42, 56, 40, 24, 72, 44, 60, 46, 72, 32, 42, 60 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	FORMULA	`a(n)=A000010[A002808(n)]`
	EXAMPLE	`100th composite is 133, phi[133]=108=a(100).`
	MATHEMATICA	`c[x_] := FixedPoint[x+PrimePi[ # ]+1&, x] Table[EulerPhi[c[w], {w, 1, 128}]`
	CROSSREFS	`Cf. A000010, A002808, A035004, A073255.` `Sequence in context: A115068 A051495 * A166362 A050469 A085730 A089002` `Adjacent sequences: A073253 A073254 A073255 * A073257 A073258 A073259`
	KEYWORD	`nonn`
	AUTHOR	`Labos E. (labos(AT)ana.sote.hu), Jul 22 2002`

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Last modified February 16 10:23 EST 2012. Contains 205904 sequences.