login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A115043
a(0)=3, a(1)=5. a(n) = a(n-1)*a(n-2) if n odd, else a(n) = a(n-1)/a(n-2).
1
3, 5, 15, 3, 45, 15, 675, 45, 30375, 675, 20503125, 30375, 622782421875, 20503125, 12768985843505859375, 622782421875, 7952299928506168842315673828125, 12768985843505859375
OFFSET
0,1
COMMENTS
All divisors >1 of the terms are also in the sequence.
FORMULA
a(n) = a(n-2)*a(n-4) if n odd. a(n)=a(n-3) if n even.
a(2n+1) = 3^Fibonacci(n+1) * 5^Fibonacci(n).
a(2n) = 3^Fibonacci(n-1) * 5^Fibonacci(n-2).
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, Feb 28 2006
EXTENSIONS
Formulas corrected by R. J. Mathar, Mar 16 2010
STATUS
approved