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Indices of terms in A093019 with value 9.
13

%I #15 Aug 17 2021 06:32:46

%S 5,10,29,34,48,53,67,72,86,91,109,114,128,133,147,152,166,171,185,190,

%T 208,213,227,232,246,251,265,270,289,294,307,312,326,331,345,350,369,

%U 374,388,393,406,411,425,430,449,454,468,473,487,492,500,519,524,538

%N Indices of terms in A093019 with value 9.

%C Integers which require a following 9 to have a valid Luhn mod 10 check digit.

%H Reinhard Zumkeller, <a href="/A093029/b093029.txt">Table of n, a(n) for n = 1..10000</a>

%H John Kilgo, <a href="https://web.archive.org/web/20040627030859/http://www.dotnetjohn.com/articles/articleid97.aspx">Using the Luhn Algorithm</a>, DotNetJohn.com.

%H Webopedia, <a href="http://www.webopedia.com/TERM/L/Luhn_formula.html">Luhn formula</a>

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Luhn_algorithm">Luhn algorithm</a>

%H <a href="/index/De#decimal_expansion">Index entries for sequences related to decimal expansion of n</a>

%F A093019(a(n)) = 9. - _Reinhard Zumkeller_, Nov 08 2014

%e 10 is in the sequence because A093019(10)=9; 109 has a valid Luhn mod 10 check digit.

%o (Haskell)

%o a093029 n = a093029_list !! (n-1)

%o a093029_list = filter ((== 9) . a093019) [0..]

%o -- _Reinhard Zumkeller_, Nov 08 2014

%Y Cf. A093017-A093028.

%K easy,nonn,base

%O 1,1

%A _Ray Chandler_, Apr 03 2004

%E Offset changed by _Reinhard Zumkeller_, Nov 08 2014