A250047 Numbers n such that m = floor(n/7) is not coprime to n and, if nonzero, m is also a term of the sequence.

2, 3, 4, 5, 6, 14, 16, 18, 20, 21, 24, 27, 28, 30, 32, 34, 35, 40, 42, 44, 45, 46, 48, 98, 100, 102, 104, 112, 114, 116, 118, 126, 128, 129, 130, 132, 140, 142, 144, 145, 146, 147, 150, 153, 168, 170, 171, 172, 174, 189, 192, 195, 196, 198, 200, 202, 210

Offset

1,1

Comments

See the comments in A250041 which all apply, except for the setting of the base, b=7. 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

Prog

(PARI) See the link
(PARI) is_rtnc(n, b=7) = {while (((m=gcd(n\b, n)) != 1), if (m == 0, return (1)); n = n\b; ); return (0); } \\ Michel Marcus, Jan 22 2015

Crossrefs

Cf. A250041 (b=10), A250046.

Other lists of right-truncatable numbers with the property RTNC(b):

A005823 (b=3), A250037 (b=4), A250039 (b=16), A250043 (b=9), A250045 (b=8), A250049 (b=6), A250051 (b=5).

Sequence in context: A334733 A039016 A249102 * A084830 A116044 A116027

Adjacent sequences: A250044 A250045 A250046 * A250048 A250049 A250050

Keyword

nonn,base,changed

Author

Stanislav Sykora, Jan 15 2015

Status

approved