A259858 A bisection of A002083.

1, 1, 3, 11, 42, 165, 654, 2605, 10398, 41550, 166116, 664299, 2656866, 10626810, 42505932, 170021123, 680079282, 2720306730, 10881206124, 43524782946, 174099048684, 696396028620, 2785583782248, 11142334464693, 44569336530174, 178277343463830, 713109368541588

Offset

0,3

References

H. Brocard, Query 4293, L'Intermédiaire des Mathématiciens, 23 (1916), 58-59. - N. J. A. Sloane, Mar 08 2022

Links

Table of n, a(n) for n=0..26.

Formula

a(0)=a(1)=1; a(2)=3; a(n) = 4*a(n-1) + ((-1)^(n-1)-3)/2 * a(floor((n-1)/2)). - Carl R. White, Oct 06 2017

Maple

A259858 := proc(n)
    A002083(2*n+1) ;
end proc:
seq(A259858(n), n=0..30) ; # R. J. Mathar, Jul 09 2015

Mathematica

a[n_] := a[n] = If[n < 3, 1 + 2 Boole@ PrimeQ@ n, 4 a[n - 1] + ((-1)^(n - 1) - 3)/2*a[Floor[(n - 1)/2]]]; Array[a, 27, 0] (* Michael De Vlieger, Oct 06 2017 *)

Crossrefs

Cf. A002083, A245094.

Sequence in context: A180907 A143464 A270561 * A359711 A117641 A200030

Adjacent sequences: A259855 A259856 A259857 * A259859 A259860 A259861

Keyword

nonn

Author

N. J. A. Sloane, Jul 07 2015

Status

approved