OFFSET
0,2
COMMENTS
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..10000
FORMULA
a(n) = floor(log_2(3n+1)).
G.f.: 1/(1-x)*(Sum_{k>=1} x^A001045(k)).
a(n) = A000523(3*n+1). - Ruud H.G. van Tol, May 12 2024
MATHEMATICA
Table[Floor[Log[2, 3*n + 1]], {n, 0, 50}] (* G. C. Greubel, Jan 08 2018 *)
PROG
(PARI) for(n=0, 30, print1(floor(log(3*n+1)/log(2)), ", ")) \\ G. C. Greubel, Jan 08 2018
(PARI) a(n) = logint(3*n+1, 2); \\ Ruud H.G. van Tol, May 12 2024
(Magma) [Floor(Log(3*n+1)/Log(2)): n in [0..30]]; // G. C. Greubel, Jan 08 2018
(Python)
def A130249(n): return (3*n+1).bit_length()-1 # Chai Wah Wu, Jun 08 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Hieronymus Fischer, May 20 2007
STATUS
approved