OFFSET
1,2
COMMENTS
Repunit R(k) is a term iff k divides R(k) (A014950).
LINKS
Giovanni Resta, Zuckerman numbers, Numbers Aplenty.
EXAMPLE
36 is a Zuckerman number as 36/(3*6) = 2, 2/2 = 1 that is a Niven number, and 36 is a term.
315 is a Zuckerman number as 315/(3*1*5) = 21, 21/(2+1) = 7 that is a Niven number, and 315 is a term.
MATHEMATICA
nivenQ[n_] := IntegerQ[n] && (sum = Plus @@ IntegerDigits[n]) > 0 && Divisible[n, sum]; Select[Range[10^5], (prod = Times @@ IntegerDigits[#]) > 0 && nivenQ[# / prod] &] (* Amiram Eldar, Apr 26 2021 *)
PROG
(PARI) isn(n) = !(n%sumdigits(n)); \\ A005349
isz(n) = my(p=vecprod(digits(n))); p && !(n % p); \\ A007602
isok(n) = isz(n) && isn(n/vecprod(digits(n))); \\ Michel Marcus, Apr 26 2021
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Bernard Schott, Apr 26 2021
EXTENSIONS
More terms from Michel Marcus, Apr 26 2021
STATUS
approved