A282024 Define k by A280864(k) = 2^n; then a(n) = A280864(k-1)/2, or -1 if that is not an integer.

1, 3, 7, 19, 41, 74, 131, 302, 523, 1031, 2458, 4132, 8209, 16381, 32832, 84614, 131101, 262139

Offset

2,2

Comments

It is known that every even number appears in A280864, and that the powers of 2 appear in increasing order.

If it were known that A280864(k-1) were always even, this would prove that A280864 contains every odd number, and so complete the proof that A280864 contains every positive number.

Links

Table of n, a(n) for n=2..19.

Crossrefs

Cf. A280864, A280746.

Sequence in context: A173114 A163572 A292775 * A356617 A086519 A090689

Adjacent sequences: A282021 A282022 A282023 * A282025 A282026 A282027

Keyword

nonn,more

Author

N. J. A. Sloane, Feb 10 2017

Status

approved