A036667 Numbers of the form 2^i*3^j, i+j even.

1, 4, 6, 9, 16, 24, 36, 54, 64, 81, 96, 144, 216, 256, 324, 384, 486, 576, 729, 864, 1024, 1296, 1536, 1944, 2304, 2916, 3456, 4096, 4374, 5184, 6144, 6561, 7776, 9216, 11664, 13824, 16384, 17496, 20736, 24576, 26244, 31104, 36864, 39366

Offset

1,2

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Formula

A069352(a(n)) mod 2 = 0. - Reinhard Zumkeller, May 16 2015

Sum_{n>=1} 1/a(n) = 7/4. - Amiram Eldar, Feb 18 2021

Mathematica

max = 40000;
Reap[Do[k = 2^i 3^j; If[k <= max && EvenQ[i+j], Sow[k]], {i, 0, Log[2, max] // Ceiling}, {j, 0, Log[3, max] // Ceiling}]][[2, 1]] // Union (* Jean-François Alcover, Aug 04 2018 *)

Prog

(Haskell)
a036667 n = a036667_list !! (n-1)
a036667_list = filter (even . flip mod 2 . a001222) a003586_list
-- Reinhard Zumkeller, May 16 2015

Crossrefs

Complement of A257999 with respect to A003586.

Intersection of A028260 and A003586.

Cf. A025620 (subsequence), A069352, A022328, A022329.

Sequence in context: A189484 A155567 A225377 * A371843 A056016 A231997

Adjacent sequences: A036664 A036665 A036666 * A036668 A036669 A036670

Keyword

nonn

Author

N. J. A. Sloane

Extensions

Offset corrected by Reinhard Zumkeller, May 16 2015

Status

approved