OFFSET
1,2
FORMULA
a(n) = ceiling(C*2^(n*(n+1)/2)) where C is a constant, C = 0.3583674393448461337061572297745... In fact, C = Sum_{k>=0} 1/2^(k*(k+1)/2) - 1/2^(k*(k+3)/2) = Sum_{k>=0} 1/2^A000217(k) - Sum_{k>=0} 1/2^A000096(k). - Benoit Cloitre, Sep 01 2002
a(n) = ceiling(C*2^(n*(n+1)/2)) where C is a constant, C = 0.3583674393448461337061572297745... - Benoit Cloitre, Sep 01 2002
MATHEMATICA
a = 1; Table[a = a*2^n - 1, {n, 14}] (* Jayanta Basu, Jul 02 2013 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Felice Russo, Aug 28 2002
EXTENSIONS
Definition corrected by Georg Fischer, Jun 19 2021
STATUS
approved