A372824 Sequence formed as follows: for each k >= 0, insert between 3^k and 3^(k+1) the greatest power of 2 than is in the interval [3^k, 3^(k+1)], and then arrange the resulting numbers in nondecreasing order.

1, 2, 3, 8, 9, 16, 27, 64, 81, 128, 243, 512, 729, 2048, 2187, 4096, 6561, 16384, 19683, 32768, 59049, 131072, 177147, 524288, 531441, 1048576, 1594323, 4194304, 4782969, 8388608, 14348907, 33554432, 43046721, 67108864, 129140163, 268435456, 387420489

Offset

0,2

Links

Table of n, a(n) for n=0..36.

Example

3^0 <= 2^1 < 3^1 < 2^3 < 3^2 < 2^4 < 3^3 < ...

Mathematica

a[n_] := If[EvenQ[n], 3^(n/2), 2^Floor[((n + 1)/2) Log[3]/Log[2]]]
Table[a[n], {n, 0, 37}]

Prog

(PARI) a(n) = if (n%2, 3^(n\2), 2^logint(3^(n/2), 2)); \\ Michel Marcus, May 23 2024

Crossrefs

Cf. A000079, A000244, A006899, A372823, A372825, A372826.

Interspersion of A000244 and A098232.

Sequence in context: A093765 A260020 A104577 * A309017 A247375 A282508

Adjacent sequences: A372821 A372822 A372823 * A372825 A372826 A372827

Keyword

nonn

Author

Clark Kimberling, May 18 2024

Status

approved