A068358 Numbers k such that the first digit of binomial(2k,k) is 1.

0, 8, 10, 13, 15, 20, 25, 27, 30, 32, 35, 37, 40, 42, 45, 47, 50, 52, 57, 62, 67, 72, 77, 82, 87, 92, 97, 102, 107, 112, 117, 122, 127, 132, 137, 142, 147, 152, 157, 162, 167, 172, 177, 182, 187, 190, 192, 195, 197, 200, 202, 205, 207, 210, 212, 215, 217, 220, 222

Offset: 1

Author

Benoit Cloitre, Feb 28 2002

Keywords

• easy
• nonn
• base

Links

• David A. Corneth, Table of n, a(n) for n = 1..10001

Crossrefs

Cf. A068359.

Programs

Mathematica

Join[{0},Select[Range[250],IntegerDigits[Binomial[2#,#]][[1]]==1&]] (* Harvey P. Dale, Dec 31 2017 *)

Extensions

a(1) = 0 inserted by Stefano Spezia, Sep 06 2022