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A257473 Composite numbers whose digits appear in their prime factors. 0


%S 22,33,55,77,95,122,132,155,202,222,272,303,312,322,326,332,333,344,

%T 366,399,505,515,555,707,731,735,777,912,955,973,995,1010,1030,1070,

%U 1090,1111,1112,1122,1131,1133,1155,1173,1177,1192,1197,1199,1202,1212,1222

%N Composite numbers whose digits appear in their prime factors.

%H L. Blomberg, in reply to E. Angelini, <a href="http://list.seqfan.eu/pipermail/seqfan/2015-April/014776.html">Any digit of a(n) is visible in a(n)'s factorization</a>, April 29, 2015.

%e See the link.

%o (PARI) is(n)=!isprime(n)&&n>1&&!#setminus(Set(digits(n)),Set(concat(apply(f->digits(f),factor(n)[,1]~)))) \\ _M. F. Hasler_, May 08 2015

%K nonn,base

%O 1,1

%A _Eric Angelini_ and _M. F. Hasler_, May 08 2015

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Last modified July 8 07:16 EDT 2020. Contains 335513 sequences. (Running on oeis4.)