A187090 - OEIS

%I #17 Jul 13 2013 12:03:47

%S 9,90,9,92,90,90,91,96,9,90,99,96,91,98,90,96,901,90,95,900,903,902,

%T 92,96,900,910,918,924,928,90,93,96,99,918,910,900,925,912,936,920,

%U 902,924,903,924,90,92,94,96,98,900,918,936,901,918,935

%N Smallest multiple of n beginning with 9.

%C a(n) is in {n, 2n, 3n, 4n, 5n, 6n, 7n, 8n, 9n, 11n, 12n, 13n, 14n, 15n, 16n, 17n, 18n, 21n, 22n, 23n, 24n, 25n, 26n, 27n, 31n, 32n, 33n, 34n, 35n, 36n, 41n, 42n, 43n, 44n, 45n, 51n, 52n, 53n, 54n, 61n, 62n, 63n, 71n, 72n, 81n}. [_Charles R Greathouse IV_, Mar 06 2011]

%H Reinhard Zumkeller, <a href="/A187090/b187090.txt">Table of n, a(n) for n = 1..10000</a>

%t f[n_] := Block[{m = n}, While[ First@ IntegerDigits@ m != 9, m += n]; m]; Array[f, 55]

%o (PARI) a(n)=forstep(k=n, 81*n, n, if(Vec(Str(k))[1]=="9", return(k))) \\ _Charles R Greathouse IV_, Mar 06 2011

%o (Haskell)

%o a187090 n = until ((== 9) . a000030) (+ n) n

%o -- _Reinhard Zumkeller_, Mar 27 2012

%Y Cf. A082811, A082792, A082794, A082795, A082796, A082797, A082798.

%Y Cf. A000030.

%K nonn,easy,base

%O 1,1

%A _Robert G. Wilson v_, Mar 06 2011