OFFSET
0,2
COMMENTS
Also, number of nodes in an n-ary tree with increasing fanout as the level increases. - Dhruv Matani, Apr 12 2012
FORMULA
a(n) = floor(D*2^(n*(n+1)/2)) where D is a constant, D=1.64163256065515386629... = Sum_{k>=0} 1/2^(k(k+1)/2) = A299998. - Benoit Cloitre, Sep 01 2002
MATHEMATICA
a = 1; Table[a = a*2^n + 1, {n, 14}] (* Jayanta Basu, Jul 02 2013 *)
PROG
(UBASIC)
25 A=1
30 for I=1 to 20
40 A=A*2^I+1
50 print A
60 next
70 end
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Felice Russo, Aug 28 2002
EXTENSIONS
Added a(0)=1. Added information from duplicate sequence A182104. - N. J. A. Sloane, Dec 28 2015
STATUS
approved