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%I #11 Apr 08 2015 11:22:16
%S 105,165,231,255,273,285,345,357,385,399,455,465,483,555,561,595,609,
%T 645,651,663,665,715,795,805,861,885,915,957,969,987,1001,1015,1023,
%U 1045,1095,1131,1185,1281,1295,1309,1311,1335,1353,1407,1443,1463,1479,1495,1515,1533,1545,1547,1551,1615,1635,1645
%N Odd numbers with prime arithmetic derivative A003415.
%C The subsequence of odd numbers in A157037.
%C In order to have a prime arithmetic derivative (satisfying (mn)' = m'n + m n', p' = 1 for primes), an odd number must have at least 3 distinct prime factors.
%H Reinhard Zumkeller, <a href="/A256673/b256673.txt">Table of n, a(n) for n = 1..10000</a>
%e a(1)=105 is the smallest odd number with prime arithmetic derivative A003415(3*5*7) = 5*7 + 3*7 + 3*5 = 71.
%o (Haskell)
%o a256673 n = a256673_list !! (n-1)
%o a256673_list = filter odd a157037_list
%o -- _Reinhard Zumkeller_, Apr 08 2015
%Y Cf. A003415, A157037.
%K nonn
%O 1,1
%A _M. F. Hasler_, Apr 07 2015
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