A225609 Recurrence a(n) = 2^n*a(n-1) + a(n-2) with a(0)=0, a(1)=1.

0, 1, 4, 33, 532, 17057, 1092180, 139816097, 35794013012, 18326674478241, 18766550459731796, 38433913668205196449, 157425329151518944386900, 1289628334843156860622681249, 21129270795495611155960953970516, 692363946716428521201685400328549537

Offset: 0

Author

Vaclav Kotesovec, Aug 22 2013

Keywords

• nonn

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..81

Crossrefs

Cf. A006116, A073587, A073588, A076131, A228465, A228467.

Programs

Mathematica

RecurrenceTable[{a[n]==2^n*a[n-1]+a[n-2],a[0]==0,a[1]==1},a,{n,0,15}]

Formula

a(n) ~ c * 2^(n^2/2 + n/2), where c = 0.52087674149344124670486211129137...