A183865 - OEIS

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A183865

n-1+ceiling(3(n+2)/5); complement of A183864.

1, 4, 8, 13, 19, 27, 36, 46, 57, 69, 83, 98, 114, 131, 149, 169, 190, 212, 235, 259, 285, 312, 340, 369, 399, 431, 464, 498, 533, 569, 607, 646, 686, 727, 769, 813, 858, 904, 951, 999, 1049, 1100, 1152, 1205, 1259, 1315, 1372, 1430, 1489, 1549, 1611, 1674, 1738, 1803, 1869, 1937, 2006, 2076, 2147, 2219

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Table of n, a(n) for n=1..60.

Index entries for linear recurrences with constant coefficients, signature (2,-1,0,0,1,-2,1).

FORMULA

a(n)=n-1+ceiling(3(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=5/3; b=0;

Table[n+Floor[(a*n+b)^(1/2)], {n, 100}]