A183873 a(n) = n-1+ceiling((1/5)n^2); complement of A183872.

1, 2, 4, 7, 9, 13, 16, 20, 25, 29, 35, 40, 46, 53, 59, 67, 74, 82, 91, 99, 109, 118, 128, 139, 149, 161, 172, 184, 197, 209, 223, 236, 250, 265, 279, 295, 310, 326, 343, 359, 377, 394, 412, 431, 449, 469, 488, 508, 529, 549, 571, 592, 614, 637, 659, 683, 706, 730, 755, 779, 805, 830, 856, 883, 909, 937, 964, 992, 1021, 1049, 1079, 1108, 1138, 1169, 1199, 1231, 1262, 1294, 1327, 1359

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

G.f.: x*(x^2+1)*(x^4-x^3-1)/((x-1)^3*(x^4+x^3+x^2+x+1)). - Colin Barker, Oct 04 2012

Mathematica

a=5; b=0;
Table[n+Floor[(a*n+b)^(1/2)], {n, 100}]
Table[n-1+Ceiling[(n*n-b)/a], {n, 80}]

Crossrefs

Cf. A183872.

Sequence in context: A288933 A129259 A077597 * A036386 A280417 A099847

Adjacent sequences: A183870 A183871 A183872 * A183874 A183875 A183876

Keyword

nonn,easy

Author

Clark Kimberling, Jan 07 2011

Status

approved