A250043 Numbers n such that m = floor(n/9) is not coprime to n and, if nonzero, m is also a term of the sequence.

2, 3, 4, 5, 6, 7, 8, 18, 20, 22, 24, 26, 27, 30, 33, 36, 38, 40, 42, 44, 45, 50, 54, 56, 57, 58, 60, 62, 63, 70, 72, 74, 76, 78, 80, 162, 164, 165, 166, 168, 170, 180, 182, 184, 185, 186, 188, 198, 200, 202, 204, 206, 216, 218, 219, 220, 222, 224, 234, 236

Offset: 1

Author

Stanislav Sykora, Jan 15 2015

Keywords

• nonn
• base

Comments

See the comments in A250041 which all apply, except for the setting of the base, b=9. In particular, they define the property RTNC(b).

Links

• Stanislav Sykora, Table of n, a(n) for n = 1..10000
• Stanislav Sykora, PARI/GP scripts for genetic threads, with code and comments
• Wikipedia, Coprime integers

Crossrefs

Cf. A250041 (b=10), A250042.

Other lists of right-truncatable numbers with the property RTNC(b): A005823 (b=3), A250037 (b=4), A250039 (b=16), A250045 (b=8), A250047 (b=7), A250049 (b=6), A250051 (b=5).

Programs

PARI

See the link

PARI

is_rtnc(n, b=9) =  {while (((m=gcd(n\b, n)) != 1), if (m == 0, return (1)); n = n\b;); return (0);} \\ Michel Marcus, Jan 17 2015