OFFSET
1,2
FORMULA
a(1)=1, a(n) = 2*(a(n-1)+1)^3-a(n-1).
EXAMPLE
a(1)=1; next cube is (a(1)+1)^3=8; "jump over" it: 8+(8-1)=15; a(2)=15; next cube is (a(2)+1)^3=4096; "jump over" it: 4096+(4096-15)=8177.
MAPLE
a(1) := 1; a(n) := 2*(a(n-1)+1)^2-a(n-1);
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Zak Seidov, Sep 26 2002
STATUS
approved