1,3

The ninth term is too large to show here.

Table of n, a(n) for n=1..8.

RecurrenceTable[{a[1]==a[2]==1, a[n]==a[n-1]+2^a[n-2]}, a, {n, 8}] (* Harvey P. Dale, May 06 2012 *)

Cf. A000225.

Sequence in context: A057188 A128548 A321358 * A209002 A106879 A249762

Adjacent sequences: A113603 A113604 A113605 * A113607 A113608 A113609

nonn

Matt Wynne (mattwyn(AT)verizon.net), Aug 25 2008

approved