OFFSET
1,2
COMMENTS
Includes all repunits.
LINKS
Christian N. K. Anderson, Table of n, a(n) for n = 1..5000
EXAMPLE
a(7) 128 is divisible by 1^2, by 2^2, and by 8^2.
MATHEMATICA
d[n_]:=IntegerDigits[n]; t={}; Do[If[!MemberQ[d[n], 0] && Union[Mod[n, d[n]^2]] == {0}, AppendTo[t, n]], {n, 11220}]; t (* Jayanta Basu, May 15 2013 *)
Select[Range[12000], DigitCount[#, 10, 0]==0&&And@@Divisible[ #, IntegerDigits[ #]^2]&] (* Harvey P. Dale, Jul 16 2018 *)
PROG
(R) isint<-function(x) x==as.integer(x)
sqalldig<-function(x) as.numeric(strsplit(as.character(x), "")[[1]])^2
divby<-function(x) ifelse(length(grep(0, x))>0, F, all(isint(x/sqalldig(x))))
which(sapply(1:1000, divby))
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Kevin L. Schwartz and Christian N. K. Anderson, May 04 2013
STATUS
approved