A025618 Numbers of form 4^i*6^j, with i, j >= 0.

1, 4, 6, 16, 24, 36, 64, 96, 144, 216, 256, 384, 576, 864, 1024, 1296, 1536, 2304, 3456, 4096, 5184, 6144, 7776, 9216, 13824, 16384, 20736, 24576, 31104, 36864, 46656, 55296, 65536, 82944, 98304, 124416, 147456, 186624, 221184, 262144, 279936

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

Sum_{n>=1} 1/a(n) = (4*6)/((4-1)*(6-1)) = 8/5. - Amiram Eldar, Sep 24 2020

a(n) ~ exp(sqrt(2*log(4)*log(6)*n)) / sqrt(24). - Vaclav Kotesovec, Sep 24 2020

Mathematica

f[upto_]:=Module[{max4=Floor[Log[upto]/Log[4]], max6 = Floor[ Log[ upto]/ Log[6]], seq}, seq=Union[4^First[#] 6^Last[#]&/@Tuples[ {Range[ 0, max4], Range[ 0, max6]}]]; Select[seq, #<=upto&]]; f[300000]  (* Harvey P. Dale, Mar 05 2011 *)

Crossrefs

Subsequence of A003586.

Sequence in context: A044858 A323043 A120375 * A133572 A121852 A321411

Adjacent sequences: A025615 A025616 A025617 * A025619 A025620 A025621

Keyword

easy,nonn

Author

David W. Wilson

Status

approved