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A053196 Cototients of even numbers. 0
1, 2, 4, 4, 6, 8, 8, 8, 12, 12, 12, 16, 14, 16, 22, 16, 18, 24, 20, 24, 30, 24, 24, 32, 30, 28, 36, 32, 30, 44, 32, 32, 46, 36, 46, 48, 38, 40, 54, 48, 42, 60, 44, 48, 66, 48, 48, 64, 56, 60, 70, 56, 54, 72, 70, 64, 78, 60, 60, 88, 62, 64, 90, 64, 82, 92, 68, 72, 94, 92, 72, 96 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

Not all even numbers arise as cototient values: see A005278.

FORMULA

a(n) = 2*n - EulerPhi[2*n] = A051953(2n)

EXAMPLE

a(6)=a(7)=a(8)=cototient[12]= cototient[14]= cototient[16]=12-4=14-6=16-8=8

CROSSREFS

A000010, A051953, A005278.

Sequence in context: A089003 A132118 A007843 * A159634 A186690 A002131

Adjacent sequences:  A053193 A053194 A053195 * A053197 A053198 A053199

KEYWORD

nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu), Mar 02 2000

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Last modified February 16 02:51 EST 2012. Contains 205860 sequences.