OFFSET
1,1
MAPLE
A130231 := proc(n)
option remember;
if n = 1 then
3;
else
a := procname(n-1) ;
for j from 1 to n-1 do
for d in convert(procname(j), base, 10) do
if d = 3 then
a := a+1 ;
end if;
end do:
end do:
a ;
end if;
end proc:
seq(A130231(n), n=1..80) ; # R. J. Mathar, Aug 06 2016
MATHEMATICA
ss=s={3}; Do[a=ss[[-1]]+Count[s, 3]; s=Join[s, IntegerDigits[a]]; AppendTo[ss, a], {n, 61}]; ss (* James C. McMahon, Feb 08 2025 *)
CROSSREFS
KEYWORD
base,easy,nonn,changed
AUTHOR
Eric Angelini, Aug 05 2007
EXTENSIONS
Corrected by R. J. Mathar, Aug 06 2016
STATUS
approved