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A248499 Numbers m that are coprime to A059995(m): floor(m/10). 6
1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 23, 25, 27, 29, 31, 32, 34, 35, 37, 38, 41, 43, 45, 47, 49, 51, 52, 53, 54, 56, 57, 58, 59, 61, 65, 67, 71, 72, 73, 74, 75, 76, 78, 79, 81, 83, 85, 87, 89, 91, 92, 94, 95, 97, 98, 101, 103, 107, 109, 111, 112 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Definition of 'being coprime' and special-case conventions are as in Wikipedia. In particular, when m<10 then floor(m/10)=0, and zero is coprime only to 1. The complementary sequence is A248500. Note: The first 57 terms a(n) coincide with A069715, but the two sequences are different.

The limit mean density of these numbers exists and equals 1223/2100 = A250031(10)/A250033(10). - Stanislav Sykora, Dec 08 2014

LINKS

Stanislav Sykora, Table of n, a(n) for n = 1..20000

S. Sykora, On some number densities related to coprimes, Stan's Library, Vol.V, Nov 2014, DOI: 10.3247/SL5Math14.005.

Wikipedia, Coprime integers

FORMULA

gcd(a(n),floor(a(n)/10)) = 1.

EXAMPLE

1 is a member because gcd(1,0)=1.

123 is not a member because gcd(123,12)=3.

165 is a member because 165 and 16 are coprime.

MATHEMATICA

Select[ Range@ 120, GCD[#, Floor[#/10]] == 1 &] (* Robert G. Wilson v, Oct 22 2014 *)

PROG

(PARI) a=vector(20000);

i=n=0; while(i++, if(gcd(i, i\10)==1, a[n++]=i; if(n==#a, break))); a

CROSSREFS

Cf. A059995, A248500, A248501, A248502, A250031, A250033.

Sequence in context: A256556 A063662 A069715 * A008716 A011531 A257946

Adjacent sequences:  A248496 A248497 A248498 * A248500 A248501 A248502

KEYWORD

nonn,base,easy

AUTHOR

Stanislav Sykora, Oct 07 2014

STATUS

approved

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Last modified August 22 12:56 EDT 2017. Contains 290948 sequences.