A038757 Earliest sequence where a(a(n))=4^n.

2, 4, 5, 16, 64, 7, 4096, 9, 65536, 11, 1048576, 13, 16777216, 15, 268435456, 256, 18, 17179869184, 20, 274877906944, 22, 4398046511104, 24, 70368744177664, 26, 1125899906842624, 28, 18014398509481984, 30, 288230376151711744, 32

Offset

1,1

Links

Table of n, a(n) for n=1..31.

Index entries for sequences of the a(a(n)) = 2n family

Example

a(7)=a(a(6))=4^6=4096

Crossrefs

Cf. A038755, A038756.

Sequence in context: A056406 A250545 A070917 * A377142 A062549 A169602

Adjacent sequences: A038754 A038755 A038756 * A038758 A038759 A038760

Keyword

nonn

Author

Henry Bottomley, May 03 2000

Status

approved