OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
MAPLE
d:= 4: # for all terms with up to d base-5 digits.
Res:= NULL;
for m from 0 to 3^(d-2)-1 do
L:= subs(1=3, convert(3^(d-2)+m, base, 3));
for i from 0 to d-2 do
for j from i+1 to d-1 do
xpos:= subs(i=NULL, j=NULL, [$0..d-1]);
x:= add(L[i]*5^xpos[i], i=1..d-2);
Res:= Res, x + 5^i+4*5^j, x+4*5^i+5^j
od od od:
sort([Res]); # Robert Israel, Jan 19 2020
MATHEMATICA
Select[Range[300], DigitCount[#, 5, 1]==DigitCount[#, 5, 4]==1&] (* Harvey P. Dale, May 04 2021 *)
PROG
(Magma) [k:k in [1..300]| Multiplicity(Intseq(k, 5), 1) eq 1 and Multiplicity(Intseq(k, 5), 4) eq 1]; // Marius A. Burtea, Jan 20 2020
CROSSREFS
KEYWORD
nonn,base
AUTHOR
STATUS
approved