A140288 The least n-digit multiple of 5^n using the decimal digits {1, 2, 3, 4, 5} exclusively.

5, 25, 125, 3125, 53125, 453125, 4453125, 14453125, 314453125, 2314453125, 22314453125, 122314453125, 4122314453125, 44122314453125, 444122314453125, 4444122314453125, 54444122314453125, 254444122314453125, 1254444122314453125, 21254444122314453125

Offset

1,1

Links

Alois P. Heinz, Table of n, a(n) for n = 1..1000

Formula

To obtain the (n+1)-th term, write the n-th term as k * 5^n. Multiply k by a multiple of 2^n to get a multiple of 5. Add the multiplicator of 2^n to the left of the n-th term.

Example

a(5) = 53125 = 17 * 5^5.

Prog

(PARI) lista(nn) = {v = vector(nn); v[1] = 5; for(k = 2, nn, j = 1; while((j*10^(k-1) + v[k-1]) % 5^k > 0, j++); v[k] = j*10^(k-1) + v[k-1]); for(k = 1, nn, print1(v[k], ", ")); } \\ Jinyuan Wang, Aug 27 2019

Crossrefs

Cf. A053312, A035014.

Sequence in context: A113996 A340538 A062875 * A306570 A061835 A321288

Adjacent sequences: A140285 A140286 A140287 * A140289 A140290 A140291

Keyword

nonn,base

Author

Michel Criton (mcriton(AT)wanadoo.fr), May 24 2008

Extensions

More terms from Alois P. Heinz, Apr 05 2017

Status

approved