OFFSET
1,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (2,-1,0,0,1,-2,1).
FORMULA
a(n)=n-1+ceiling((2/5)(-1/2+n^2)).
MATHEMATICA
a=5/2; b=1/2;
Table[n+Floor[(a*n+b)^(1/2)], {n, 80}]
Table[n-1+Ceiling[(n*n-b)/a], {n, 70}]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jan 07 2011
STATUS
approved