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

Author

N. J. A. Sloane, Feb 10 2017

Keywords

• nonn
• more

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.

Crossrefs

Cf. A280864, A280746.