A266409 a(n) = (A003309(n+2)-1) / 2; numbers n such that 2n+1 is a Ludic number (in A003309).

1, 2, 3, 5, 6, 8, 11, 12, 14, 18, 20, 21, 23, 26, 30, 33, 35, 38, 41, 44, 45, 48, 53, 57, 59, 60, 63, 65, 71, 74, 78, 80, 86, 87, 89, 90, 96, 104, 105, 110, 111, 113, 116, 117, 119, 123, 128, 132, 138, 141, 143, 150, 153, 156, 164, 165, 168, 170, 176, 179, 180, 188, 191, 194, 198, 203, 207, 209, 210, 215

Offset: 1

Author

Antti Karttunen, Jan 28 2016

Keywords

• nonn

Comments

Ludic numbers from A003309(2) = 3 onward, decremented by one, then halved.

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10226

Crossrefs

Complement: A266410.

Cf. A003309, A192490.

Cf. A266350 (least monotonic left inverse).

Cf. permutations A266418, A266638.

Cf. also A005097.

Formula

a(n) = (A003309(n+2)-1) / 2.

Other identities. For all n >= 1:

A266350(a(n)) = n.