A111202 a(1)=2 then a(n)=a(n-1)+3 if n is already in the sequence, a(n)=a(n-2)+1 otherwise.

2, 5, 3, 6, 9, 12, 10, 13, 16, 19, 17, 20, 23, 21, 24, 27, 30, 28, 31, 34, 37, 35, 38, 41, 39, 42, 45, 48, 46, 49, 52, 50, 53, 56, 59, 57, 60, 63, 66, 64, 67, 70, 68, 71, 74, 77, 75, 78, 81, 84, 82, 85, 88, 86, 89, 92, 95, 93, 96, 99, 97, 100, 103, 106, 104, 107, 110, 113, 111

Offset

1,1

Links

Table of n, a(n) for n=1..69.

Formula

a(n)=phi*n+O(1) where phi=(1+sqrt(5))/2

Prog

(PARI) an=vector(100); a(n)=if(n<0, 0, an[n]); an[1]=2; for(n=2, 100, an[n]=if(setsearch(Set(vector(n-1, i, a(i))), n), a(n-1)+3, a(n-2)+1))

Crossrefs

Sequence in context: A358838 A359008 A239970 * A194280 A163362 A243061

Adjacent sequences: A111199 A111200 A111201 * A111203 A111204 A111205

Keyword

nonn

Author

Benoit Cloitre, Oct 24 2005

Status

approved