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A100447 Bisection of A000031. 2
2, 4, 8, 20, 60, 188, 632, 2192, 7712, 27596, 99880, 364724, 1342184, 4971068, 18512792, 69273668, 260301176, 981706832, 3714566312, 14096303344, 53634713552, 204560302844, 781874936816, 2994414645860, 11488774559636 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..24.

MAPLE

with(numtheory):seq((1/(2*n+1))*add(phi(d)*2^((2*n+1)/d), d=divisors(2*n+1)), n=0..30); (C. Ronaldo)

CROSSREFS

Cf. A000031, A100446. Equals 2*A026119.

Sequence in context: A000116 A302862 A006407 * A241891 A112278 A059731

Adjacent sequences:  A100444 A100445 A100446 * A100448 A100449 A100450

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Nov 21 2004

EXTENSIONS

More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 19 2005

STATUS

approved

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Last modified October 20 04:05 EDT 2018. Contains 316378 sequences. (Running on oeis4.)