OFFSET
1,2
LINKS
Harry J. Smith, Table of n, a(n) for n = 1..1000
EXAMPLE
118 is in the sequence because the 4th power of 118 is 193877776 and 1*9*3*8*7*7*7*7*6 = 3111696 = 42^4.
MATHEMATICA
Do[a = Apply[Times, IntegerDigits[n^2]]; If[ a != 0 && IntegerQ[a^(1/2)], Print[n]], {n, 1, 10^4} ]
d4pQ[n_]:=Module[{t=Times@@IntegerDigits[n^4]}, t!=0&&IntegerQ[Surd[t, 4]]]; Select[Range[70000], d4pQ] (* Harvey P. Dale, Feb 20 2018 *)
PROG
(PARI) isok(k)={my(p=vecprod(digits(k^4))); p && ispower(p, 4)} \\ Harry J. Smith, Mar 20 2010
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Robert G. Wilson v, Jan 15 2002
STATUS
approved