A250036 Numbers n such that m = floor(n/4) is coprime to n and, if nonzero, m is also a term of the sequence.

1, 4, 5, 6, 7, 17, 19, 21, 22, 23, 25, 29, 30, 31, 69, 70, 71, 77, 78, 79, 85, 86, 89, 91, 93, 94, 95, 101, 102, 103, 117, 118, 119, 121, 125, 126, 127, 277, 278, 281, 283, 285, 286, 287, 309, 310, 311, 313, 317, 318, 319, 341, 342, 343, 345, 347, 357, 358

Offset

1,2

Comments

See the comments in A250040 which all apply, except for the setting of the base, b=4. In particular, they define the property RTC(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_rtc(n, b=4) =  {while (((m=gcd(n\b, n)) == 1), if (m == 0, return (1)); if ((n=n\b) == 0, return (1)); ); return (0); } \\ Michel Marcus, Jan 18 2015

Crossrefs

Cf. A250037, A250040.

Other lists of right-truncatable numbers with the property RTC(b): A250038 (b=16), A250040 (b=10), A250042 (b=9), A250044 (b=8), A250046 (b=7), A250048 (b=6), A250050 (b=5).

Sequence in context: A327082 A154787 A233035 * A107759 A161627 A030667

Adjacent sequences: A250033 A250034 A250035 * A250037 A250038 A250039

Keyword

nonn,base

Author

Stanislav Sykora, Dec 07 2014

Status

approved