A244217 Numbers n less than twice the largest Catalan number that is less than or equal to n.

1, 2, 3, 5, 6, 7, 8, 9, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 132, 133, 134

Offset: 1

Author

Antti Karttunen, Jun 23 2014

Keywords

• nonn

Comments

Equally: Numbers k such that if m is the largest Catalan number <= k [= A081290(k)], then k < 2*m.

Numbers k such that the Greedy Catalan Base representation of k (A014418(k)) starts with digit 1.

Examples

			41 is not a member, because the largest Catalan number less than or equal to 41 is C(4) = 14, and 41 is not less than 2*14 = 28.
42 is a member, because the largest Catalan number less than or equal to 42 is C(5) = 42 itself, and 42 certainly is less than 2*42 = 84.
See also the examples given for the complement of this sequence: A244216.
		

Links

• Antti Karttunen, Table of n, a(n) for n = 1..6918

Crossrefs

Positions of nonzeros in A244215.

Complement of A244216.

Cf. A000108 (a subsequence), A014418, A081290, A244314.