A154534 - OEIS

%I #28 Apr 16 2015 06:34:10

%S 77,105,201,203,205,207,209,301,303,305,309,403,405,407,501,505,507,

%T 603,605,609,703,705,707,779,801,803,805,807,899,901,903,905,909,989,

%U 1011,1015,1017,1023,1025,1027,1029,1035,1037,1041,1043,1045,1047,1053,1055

%N Odd nonprimes n with smallest digit of n + number of smallest digits of n = odd nonprime.

%H Alois P. Heinz, <a href="/A154534/b154534.txt">Table of n, a(n) for n = 1..1000</a>

%e If n=77=odd nonprime, 7=7 and 7+2=9=odd nonprime, thus 77 is in the sequence.  If n=105=odd nonprime, 0<1<5 and 0+1=1=odd nonprime, thus 105 is in the sequence.

%p filter:= proc(n) local L,m,q;

%p   if isprime(n) then return false fi;

%p   L:= convert(n,base,10);

%p   m:= min(L);

%p   q:= m + numboccur(L,m);

%p   q::odd and not isprime(q)

%p end proc:

%p select(filter, [seq(2*i+1,i=0..1000)]); # _Robert Israel_, Apr 15 2015

%Y Cf. A141468.

%K nonn,base

%O 1,1

%A _Juri-Stepan Gerasimov_, Jan 11 2009

%E Edited by _Alois P. Heinz_, Apr 15 2015