A081842 a(1)=0, a(n)=a(n-1)+4 if n is already in the sequence, a(n)=a(n-1)+3 otherwise.

0, 3, 7, 10, 13, 16, 20, 23, 26, 30, 33, 36, 40, 43, 46, 50, 53, 56, 59, 63, 66, 69, 73, 76, 79, 83, 86, 89, 92, 96, 99, 102, 106, 109, 112, 116, 119, 122, 125, 129, 132, 135, 139, 142, 145, 149, 152, 155, 158, 162, 165, 168, 172, 175, 178, 182, 185, 188, 192, 195

Offset

1,2

Links

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

Formula

a(n)=floor(r*n-(4*r-1)/(r+1)) where r= (1/2) *(3+sqrt(13))

Mathematica

Module[{seq={0}, n=2}, Do[If[MemberQ[seq, n], AppendTo[seq, Last[seq]+4], AppendTo[seq, Last[seq]+3]]; n++, {60}]; seq] (* Harvey P. Dale, Nov 20 2012 *)

Crossrefs

Sequence in context: A370756 A226723 A029918 * A160591 A297466 A198267

Adjacent sequences: A081839 A081840 A081841 * A081843 A081844 A081845

Keyword

nonn

Author

Benoit Cloitre, Apr 11 2003

Status

approved