Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #8 Jan 11 2018 23:47:07
%S -1,-1,0,0,2,6,9,36,40,200,205,1230,1236,8652,8659,69272,69280,623520,
%T 623529,6235290,6235300,68588300,68588311,823059732,823059744,
%U 10699776672,10699776685,149796873590,149796873604,2246953104060,2246953104075,35951249665200,35951249665216
%N Multiply by 1, add 1, multiply by 2, add 2, etc.
%C Bisections: A038156 and A038157.
%H Robert Israel, <a href="/A082459/b082459.txt">Table of n, a(n) for n = 0..898</a>
%F From _Robert Israel_, Jan 11 2018: (Start)
%F a(2*k) = e*Gamma(k+1,1) - k! - 1.
%F a(2*k+1) = e*Gamma(k+2,1) - (k+1)! - k - 2. (End)
%p seq(op(simplify([exp(1)*GAMMA(k+1,1)-k!-1, exp(1)*GAMMA(k+2,1)-(k+1)!-k-2])),k=0..20); # _Robert Israel_, Jan 11 2018
%t FoldList[If[OddQ@ #2, #1 ((#2 + 1)/2), #1 + #2/2] &, -1, Range@ 31] (* _Michael De Vlieger_, Jan 11 2018 *)
%Y Cf. A019464 - A019466.
%K sign
%O 0,5
%A _Vladeta Jovovic_, Apr 25 2003