OFFSET
1,1
COMMENTS
A primitive Niven number (A356349) is a Niven number (A005349) that is not ten times another Niven number.
For any k > 0, there exist terms with k trailing zeros; for example R_2^k * 10^k (where R = A002275), so this sequence is infinite.
The smallest primitive Niven number ending with m zeros is A358256(m).
LINKS
Giovanni Resta, Harshad numbers.
EXAMPLE
150 is a term as 150 is a Niven number and 15 is not a Niven number.
180 is not a term as 180 is a Niven number but 18 is also a Niven number.
MATHEMATICA
Select[10*Range[200], Divisible[#, (s = Plus @@ IntegerDigits[#])] && ! Divisible[#/10, s] &] (* Amiram Eldar, Nov 05 2022 *)
PROG
(PARI) isniven(n) = n%sumdigits(n)==0; \\ A005349
isok(m) = !(m % 10) && isniven(m) && !isniven(m/10); \\ Michel Marcus, Nov 05 2022
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Bernard Schott, Nov 05 2022
STATUS
approved