A362343 Sequence that alternately doubles and squares the previous number; a(0) = 1.

1, 2, 4, 8, 64, 128, 16384, 32768, 1073741824, 2147483648, 4611686018427387904, 9223372036854775808, 85070591730234615865843651857942052864, 170141183460469231731687303715884105728, 28948022309329048855892746252171976963317496166410141009864396001978282409984

Offset

0,2

Links

Table of n, a(n) for n=0..14.

Formula

a(0) = 1; a(n) = a(n-1)*2 if n is odd, otherwise a(n) = a(n-1)^2.

a(n) = 2^A075427(n-1), for n>=1.

Prog

(Python)
def A362343(n): return 1<<((1<<(n>>1)+1)-1 if n&1 else (1<<(n>>1)+1)-2) # Chai Wah Wu, Apr 23 2023

Crossrefs

Cf. A075427.

Subsequence of A000079.

Sequence in context: A263451 A339951 A069027 * A065549 A067507 A320898

Adjacent sequences: A362340 A362341 A362342 * A362344 A362345 A362346

Keyword

nonn,easy

Author

Christopher Roat, Apr 17 2023

Status

approved