A082797 Smallest multiple of n beginning with 7.

7, 70, 72, 72, 70, 72, 7, 72, 72, 70, 77, 72, 78, 70, 75, 704, 714, 72, 76, 700, 714, 704, 713, 72, 75, 78, 702, 700, 725, 720, 713, 704, 726, 714, 70, 72, 74, 76, 78, 720, 738, 714, 731, 704, 720, 736, 705, 720, 735, 700, 714, 728, 742, 702, 715

Offset: 1

Author

Amarnath Murthy, Apr 20 2003

Keywords

• base
• easy
• nonn

Comments

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, 41n, 42n, 43n, 44n, 51n, 52n, 53n, 61n, 62n}. [Charles R Greathouse IV, Mar 06 2011]

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A082794, A082795, A082796, A082798.

Cf. A000030.

Programs

Haskell

a082797 n = until ((== 7) . a000030) (+ n) n
-- Reinhard Zumkeller, Mar 27 2012

Mathematica

f[n_] := Block[{m = n}, While[ First@ IntegerDigits@ m != 7, m += n]; m]; Array[f, 55] (* Robert G. Wilson v *)

PARI

a(n)=forstep(k=n, 62*n, n, if(Vec(Str(k))[1]=="7", return(k))) \\ Charles R Greathouse IV, Mar 06 2011

Extensions

Corrected and extended by Sean A. Irvine, Mar 06 2011