A078913 a(1)=a(2)=1, a(n)=a(n-1)+a(n-2) if n is not congruent to 3, a(n)=a(n-1)+a(n/3) if n is congruent to 3.

1, 1, 2, 3, 5, 6, 11, 17, 19, 36, 55, 58, 113, 171, 176, 347, 523, 529, 1052, 1581, 1592, 3173, 4765, 4782, 9547, 14329, 14348, 28677, 43025, 43061, 86086, 129147, 129202, 258349, 387551, 387609, 775160, 1162769, 1162882, 2325651, 3488533, 3488704

Offset

1,3

Links

Table of n, a(n) for n=1..42.

Formula

a(3n) is asymptotic to c*3^n, a(3n+1) to 2*c*3^n, a(3n+2) to 3*c*3^n where c=0.729407718249558020561155714549683618764251558505616....

Prog

(PARI) a(n)=if(n<3, 1, a(n-1)+if(n%3, a(n-2), a(n/3)))

Crossrefs

Sequence in context: A268935 A112598 A346721 * A174100 A359599 A114339

Adjacent sequences: A078910 A078911 A078912 * A078914 A078915 A078916

Keyword

nonn

Author

Benoit Cloitre, Jan 11 2003

Status

approved