A184013 n - 1 + ceiling((4+n^2)/5); complement of A184012.

1, 3, 5, 7, 10, 13, 17, 21, 25, 30, 35, 41, 47, 53, 60, 67, 75, 83, 91, 100, 109, 119, 129, 139, 150, 161, 173, 185, 197, 210, 223, 237, 251, 265, 280, 295, 311, 327, 343, 360, 377, 395, 413, 431, 450, 469, 489, 509, 529, 550, 571, 593, 615, 637, 660, 683, 707, 731, 755, 780, 805, 831, 857, 883, 910, 937, 965, 993, 1021, 1050, 1079, 1109, 1139, 1169, 1200, 1231, 1263, 1295, 1327, 1360

Offset

1,2

Links

Table of n, a(n) for n=1..80.

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

Cf. A184012.

Sequence in context: A072166 A077000 A195311 * A057672 A112509 A296846

Adjacent sequences: A184010 A184011 A184012 * A184014 A184015 A184016

Keyword

nonn,easy

Author

Clark Kimberling, Jan 08 2011

Status

approved