OFFSET
1,1
EXAMPLE
a(1) = 5 = (2+3).
a(2) = 13 = (2+3)+(3+5).
a(3) = 31 = (2+3)+(3+5)+(7+11).
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, Feb 07 2005
EXTENSIONS
Edited and extended by Ray Chandler, Feb 12 2005
STATUS
approved