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((4+n^2)/5).
a(n) = +2 a(n-1) -a(n-2) +a(n-5) -2 a(n-6) +a(n-7). - R. J. Mathar, Mar 11 2012
MATHEMATICA
a=5; b=-4;
Table[n+Floor[(a*n+b)^(1/2)], {n, 100}]
Table[n-1+Ceiling[(n*n-b)/a], {n, 80}]
LinearRecurrence[{2, -1, 0, 0, 1, -2, 1}, {1, 3, 5, 7, 10, 13, 17}, 80] (* Harvey P. Dale, Mar 17 2023 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jan 08 2011
STATUS
approved