|
|
A259346
|
|
If n = 2^k then a(n) = 3^k, otherwise a(n) = 0.
|
|
2
|
|
|
1, 3, 0, 9, 0, 0, 0, 27, 0, 0, 0, 0, 0, 0, 0, 81, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 243, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 729, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
LINKS
|
|
|
FORMULA
|
Completely multiplicative with a(2) = 3, a(p) = 0 for odd prime p. - Andrew Howroyd, Jul 27 2018
|
|
MATHEMATICA
|
a[n_] := With[{k = IntegerExponent[n, 2]}, If[n == 2^k, 3^k, 0]];
|
|
PROG
|
(PARI) a(n)={my(e=valuation(n, 2)); if(n == 2^e, 3^e, 0)} \\ Andrew Howroyd, Jul 27 2018
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy,mult
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|