A342978 Zeroless numbers k ordered according to k/A007954(k), and in case of ties by k, where A007954(k) is the product of digits of k.

1, 2, 3, 4, 5, 6, 7, 8, 9, 99, 89, 79, 69, 59, 49, 98, 999, 88, 899, 78, 799, 68, 699, 39, 58, 599, 48, 9999, 989, 97, 499, 998, 8999, 889, 87, 898, 789, 7999, 77, 38, 798, 689, 67, 6999, 29, 698, 57, 589, 399, 5999, 598, 47, 99999, 9899, 489, 9989, 4999, 9998

Offset

1,2

Links

David A. Corneth, Table of n, a(n) for n = 1..10000

David A. Corneth, PARI program

Example

For k=1 to 9, k/A007954(k) = 1, the least possible value, so a(k)=k for k=1 to 9.
Then we have 99, 89, 79, 69, 59, 49, 98 with 1.22, 1.23, 1.25, 1.27, 1.31, 1.36, 1.36.

Prog

(PARI) \\ up to d digits
nonzero(n) = vecmin(digits(n));
pd(n) = n/vecprod(digits(n));
lista(d) = {my(lim = 10^d-1, vk = select(nonzero, [1..lim]), vpk = vector(#vk, k, pd(vk[k])), vsk = vecsort(vpk, , 1)); my(vall = vector(#vsk, k, vk[vsk[k]])); my(out = List(), k = 1); while(vall[k] != lim, listput(out, vall[k]); k++); listput(out, vall[k]); Vec(out); }
(PARI) See Corneth link \\ David A. Corneth, Apr 02 2021

Crossrefs

Cf. A007954 (product of decimal digits), A052382 (zeroless numbers).

Sequence in context: A071271 A066492 A348834 * A281091 A271569 A239138

Adjacent sequences: A342975 A342976 A342977 * A342979 A342980 A342981

Keyword

nonn,look,base

Author

Michel Marcus, Apr 02 2021

Status

approved