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A184109
n + ceiling(n^2/9); complement of A184108.
2
2, 3, 4, 6, 8, 10, 13, 16, 18, 22, 25, 28, 32, 36, 40, 45, 50, 54, 60, 65, 70, 76, 82, 88, 95, 102, 108, 116, 123, 130, 138, 146, 154, 163, 172, 180, 190, 199, 208, 218, 228, 238, 249, 260, 270, 282, 293, 304, 316, 328, 340, 353, 366, 378, 392, 405, 418, 432, 446, 460, 475, 490, 504, 520, 535, 550, 566, 582, 598, 615, 632, 648, 666, 683, 700, 718, 736, 754, 773, 792, 810, 830, 849, 868, 888, 908, 928, 949, 970, 990
OFFSET
1,1
FORMULA
G.f.: (2*x-x^2+x^4+x^7-x^9)/(1-2*x+x^2-x^9+2*x^10-x^11). - Matthew House, Feb 15 2017
a(n) = +2 a(n-1) -a(n-2) +a(n-9) -2 a(n-10) +a(n-11). - R. J. Mathar, Mar 11 2012
MATHEMATICA
a=9; b=-9;
Table[n+Floor[(a*n+b)^(1/2)], {n, 100}]
Table[n-1+Ceiling[(n^2-b)/a], {n, 90}]
Table[n+Ceiling[n^2/9], {n, 100}] (* or *) LinearRecurrence[{2, -1, 0, 0, 0, 0, 0, 0, 1, -2, 1}, {2, 3, 4, 6, 8, 10, 13, 16, 18, 22, 25}, 100] (* Harvey P. Dale, Jun 25 2021 *)
PROG
(PARI) a(n)=a(n)=(n^2+9*n+8)\9 \\ Charles R Greathouse IV, Feb 15 2017
CROSSREFS
Complement of A184108.
Sequence in context: A352929 A096061 A100919 * A214780 A024174 A008739
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jan 09 2011
STATUS
approved