A285452 Least number x such that x^n has n digits equal to k. Case k=5.

5, 75, 136, 273, 435, 725, 715, 1696, 1205, 2965, 3705, 1692, 1953, 4508, 5915, 10948, 10124, 13734, 14696, 20727, 17653, 22122, 35855, 24016, 27643, 33171, 34153, 64855, 62667, 81285, 97193, 45112, 98735, 88505, 123345, 98556, 80633, 157034, 102908, 28383, 176175

Offset

1,1

Links

Martin Gossow, Table of n, a(n) for n = 1..100

Example

a(4) = 273 because 273^4 = 5554571841 has 4 digits '5' and is the least number to have this property.

Maple

P:=proc(q, h) local a, j, k, n, t; for n from 1 to q do for k from 1 to q do
a:=convert(k^n, base, 10); t:=0; for j from 1 to nops(a) do if a[j]=h then t:=t+1; fi; od;
if t=n then print(k); break; fi; od; od; end: P(10^9, 5);

Mathematica

With[{k = 5}, Table[x = 1; While[DigitCount[x^n, 10, k] != n, x++]; x, {n, 41}]] (* Michael De Vlieger, May 01 2017 *)

Prog

(PARI) A285452vec=(n, {k=5})->{my(L:list, c); L=List(); for(t=1, n, forstep(y=1, +oo, 1, c=digits(y^t); if(sum(j=1, #c, c[j]==k)==t, listput(L, y); break()))); return(Vec(L))} \\ R. J. Cano, Apr 30 2017

Crossrefs

Sequence in context: A376112 A156703 A380925 * A048350 A030991 A216093

Adjacent sequences: A285449 A285450 A285451 * A285453 A285454 A285455

Keyword

nonn,base,easy

Author

Paolo P. Lava, Apr 19 2017

Status

approved