A183859 a(n) = n - 1 + ceiling((n^2)/3); complement of A183858.

1, 3, 5, 9, 13, 17, 23, 29, 35, 43, 51, 59, 69, 79, 89, 101, 113, 125, 139, 153, 167, 183, 199, 215, 233, 251, 269, 289, 309, 329, 351, 373, 395, 419, 443, 467, 493, 519, 545, 573, 601, 629, 659, 689, 719, 751, 783, 815, 849, 883, 917, 953, 989, 1025, 1063, 1101

Offset

1,2

Links

Table of n, a(n) for n=1..56.

Index entries for linear recurrences with constant coefficients, signature (2,-1,1,-2,1).

Formula

a(n) = n - 1 + ceiling((n^2)/3).

Mathematica

a=3; b=0;
Table[n+Floor[(a*n+b)^(1/2)], {n, 100}]
Table[n-1+Ceiling[(n*n-b)/a], {n, 80}]

Crossrefs

Cf. A183858.

Sequence in context: A196094 A063915 A340520 * A096228 A185170 A211340

Adjacent sequences: A183856 A183857 A183858 * A183860 A183861 A183862

Keyword

nonn,easy

Author

Clark Kimberling, Jan 07 2011

Status

approved