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A184013
n - 1 + ceiling((4+n^2)/5); complement of A184012.
1
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
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
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jan 08 2011
STATUS
approved