A367361 Comma transform of powers of 2.

12, 24, 48, 81, 63, 26, 41, 82, 65, 21, 42, 84, 68, 21, 43, 86, 61, 22, 45, 81, 62, 24, 48, 81, 63, 26, 41, 82, 65, 21, 42, 84, 68, 21, 43, 86, 61, 22, 45, 81, 62, 24, 48, 81, 63, 27, 41, 82, 65, 21, 42, 84, 69, 21, 43, 87, 61, 22, 45, 81, 62, 24, 49, 81, 63, 27, 41, 82, 65, 21, 42, 84, 69, 21, 43, 87, 61, 23, 46, 81

Offset: 0

Author

N. J. A. Sloane, Nov 22 2023

Keywords

• nonn
• base

Comments

See A367360 for further information.

Links

• Michael De Vlieger, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A000079, A000689, A008952, A166499, A367360.

Programs

Mathematica

FromDigits /@ Partition[Rest@ Flatten[{First[#], Last[#]} & /@ IntegerDigits[2^Range[0, 120]]], 2, 2] (* Michael De Vlieger, Nov 22 2023 *)

Python

from itertools import count, islice, pairwise
def S(): yield from (str(2**i) for i in count(0))
def agen(): yield from (int(t[-1]+u[0]) for t, u in pairwise(S()))
print(list(islice(agen(), 80))) # Michael S. Branicky, Nov 22 2023

Python

def A367361(n): return (60,20,40,80)[n&3]+int(str(1<Chai Wah Wu, Dec 22 2023

Formula

a(n) = 10 * A000689(n) + A008952(n+1). - Alois P. Heinz, Nov 22 2023