OFFSET
1,1
FORMULA
a(n) = n + floor(sqrt(5n-4))
MATHEMATICA
a=5; b=-4;
Table[n+Floor[(a*n+b)^(1/2)], {n, 100}]
Table[n-1+Ceiling[(n*n-b)/a], {n, 70}]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jan 08 2011
STATUS
approved