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A080837 Jouka numbers: either the number is divisible by 7 or 11 or has a 7 in its decimal representation. 1
7, 11, 14, 17, 21, 22, 27, 28, 33, 35, 37, 42, 44, 47, 49, 55, 56, 57, 63, 66, 67, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 84, 87, 88, 91, 97, 98, 99, 105, 107, 110, 112, 117, 119, 121, 126, 127, 132, 133, 137, 140, 143, 147, 154, 157, 161, 165, 167, 168, 170 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Jouka numbers are used in drinking games. Whenever a person wrongly identifies a jouka number he or she has to drink a beer.

LINKS

Nathaniel Johnston, Table of n, a(n) for n = 1..10000

FORMULA

a(n) ~ n. - Charles R Greathouse IV, Sep 10 2015

EXAMPLE

a(1) = 7, a(2) = 11, since 7 is the first jouka number (divisible by 7) and 11 is the second.

MAPLE

A080837 := proc(n) option remember: local k: if(n=1)then return 7: fi: for k from procname(n-1)+1 do if(k mod 7=0 or k mod 11=0 or member(7, convert(k, base, 10)))then return k: fi: od: end: seq(A080837(n), n=1..60); # Nathaniel Johnston, May 26 2011

MATHEMATICA

Select[Range[200], Divisible[#, 7]||Divisible[#, 11]||DigitCount[ #, 10, 7]> 0&] (* Harvey P. Dale, Jan 14 2017 *)

PROG

(PARI) is(n)=gcd(n, 77)>1 || setsearch(Set(digits(n)), 7) \\ Charles R Greathouse IV, Sep 10 2015

(Python)

def ok(n): return n%7 == 0 or n%11 == 0 or '7' in str(n)

print(list(filter(ok, range(1, 171)))) # Michael S. Branicky, Jul 11 2021

CROSSREFS

Sequence in context: A153049 A065105 A118797 * A168135 A225858 A120687

Adjacent sequences:  A080834 A080835 A080836 * A080838 A080839 A080840

KEYWORD

nonn,easy,base

AUTHOR

Sander and Pieter (eendebak(AT)math.uu.nl), Mar 28 2003

EXTENSIONS

Terms after a(34) from Nathaniel Johnston, May 26 2011

STATUS

approved

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Last modified September 25 09:40 EDT 2021. Contains 347654 sequences. (Running on oeis4.)