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 A062016 Numbers with all odd digits which can be factored into two numbers > 1 with odd digits. 2

%I #12 Nov 22 2016 21:59:54

%S 9,15,33,35,39,51,55,57,75,77,91,93,95,99,111,117,119,133,135,153,155,

%T 159,171,175,177,195,315,333,339,351,355,357,371,375,393,395,399,511,

%U 513,519,531,537,539,553,555,573,575,579,591,595,597,711,715,755,775,777,791,795,917,931,933,935,939,951,955,957,959,973,975

%N Numbers with all odd digits which can be factored into two numbers > 1 with odd digits.

%H Matthew House, <a href="/A062016/b062016.txt">Table of n, a(n) for n = 1..10000</a>

%e 95 = 19*5 is OK but 115 = 23*5 and 17*5 = 85 are not.

%p dmax:= 4: # to get all terms of up to dmax digits

%p S[1]:= [1,3,5,7,9]:

%p for d from 2 to dmax do

%p S[d]:= map(t -> seq(10*t+j,j=1..9,2), S[d-1])

%p od:

%p T:= {seq(op(S[i]),i=1..dmax)} minus {1}:

%p R:= T intersect {seq(seq(T[i]*T[j],j=1..i),i=1..nops(T))}:

%p sort(convert(R,list)); # _Robert Israel_, Nov 22 2016

%K nonn,base,easy

%O 1,1

%A _Amarnath Murthy_, Jun 01 2001

%E More terms from _Matthew Conroy_, Jun 11 2001

%E Offset corrected by and more terms from _Matthew House_, Nov 22 2016

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Last modified November 28 09:27 EST 2023. Contains 367412 sequences. (Running on oeis4.)