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A081982 Primes p such that p+1 is divisible by the digital product (of nonzero digits) of p. 6

%I #14 Nov 10 2017 21:14:28

%S 11,23,101,113,131,167,211,233,311,431,863,1013,1021,1031,1061,1103,

%T 1201,1217,1223,1259,1301,1601,1619,1637,1721,1823,2003,2011,2111,

%U 2687,3011,3023,3203,4111,4703,6011,6047,6101,6173,6263,6911,7013

%N Primes p such that p+1 is divisible by the digital product (of nonzero digits) of p.

%C Contains A020449 and A107612 (except 2). - _Robert Israel_, Nov 09 2017

%H Robert Israel, <a href="/A081982/b081982.txt">Table of n, a(n) for n = 1..10000</a>

%e 167 is a term as 168 is divisible by 1*6*7 = 42.

%p filter:= proc(n)

%p isprime(n) and

%p n+1 mod convert(subs(0=NULL,convert(n,base,10)),`*`) = 0

%p end proc:

%p select(filter, [seq(i,i=3..10000,2)]); # _Robert Israel_, Nov 09 2017

%o (PARI) isok(p) = isprime(p) && (d=digits(p)) && !((p+1) % prod(k=1, #d, if (d[k], d[k], 1))); \\ _Michel Marcus_, Nov 09 2017

%Y Cf. A020449, A081981, A081983, A081984, A081986, A081987, A107612, A101987.

%K base,nonn

%O 1,1

%A _Amarnath Murthy_, Apr 04 2003

%E More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 06 2003

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Last modified April 24 18:17 EDT 2024. Contains 371962 sequences. (Running on oeis4.)