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%I #4 May 12 2015 17:57:21
%S 15,35,63,99,105,143,195,255,315,323,399,483,575,675,693,783,899,945,
%T 1023,1155,1287,1295,1443,1599,1763,1935,2115,2145,2303,2499,2703,
%U 2915,3135,3315,3363,3465,3599,3843,4095,4355,4623,4845,4899,5183,5475,5775,6083
%N Numbers which are the product of at least two consecutive odd numbers > 1.
%H Reinhard Zumkeller, <a href="/A257836/b257836.txt">Table of n, a(n) for n = 1..10000</a>
%e . | | ----- Factorizations into ... --------------
%e . n | a(n) | prime powers | consecutive odd numbers
%e . ----+-------+--------------------+--------------------------
%e . 1 | 15 | 3 * 5 | 3 * 5
%e . 2 | 35 | 5 * 7 | 5 * 7
%e . 3 | 63 | 3^2 * 7 | 7 * 9
%e . 4 | 99 | 3^2 * 11 | 9 * 11
%e . 5 | 105 | 3 * 5 * 7 | 3 * 5 * 7
%e . 6 | 143 | 11 * 13 | 11 * 13
%e . 7 | 195 | 3 * 5 * 13 | 13 * 15
%e . 8 | 255 | 3 * 5 * 17 | 15 * 17
%e . 9 | 315 | 3^2 * 5 * 7 | 5 * 7 * 9
%e . 10 | 323 | 17 * 19 | 17 * 19
%e . 11 | 399 | 3 * 7 * 19 | 19 * 21
%e . 12 | 483 | 3 * 7 * 23 | 21 * 23
%e . 13 | 575 | 5^2 * 23 | 23 * 25
%e . 14 | 675 | 3^3 * 5^2 | 25 * 27
%e . 15 | 693 | 3^2 * 7 * 11 | 7 * 9 * 11
%e . 16 | 783 | 3^3 * 29 | 27 * 29
%e . 17 | 899 | 29 * 31 | 29 * 31
%e . 18 | 945 | 3^3 * 5 * 7 | 3 * 5 * 7 * 9
%e . 19 | 1023 | 3 * 11 * 31 | 31 * 33
%e . 20 | 1155 | 3 * 5 * 7 * 11 | 33 * 35
%e . 21 | 1287 | 3^2 * 11 * 13 | 9 * 11 * 13
%e . 22 | 1295 | 5 * 7 * 37 | 35 * 37
%e . 23 | 1443 | 3 * 13 * 37 | 37 * 39
%e . 24 | 1599 | 3 * 13 * 41 | 39 * 41
%e . 25 | 1763 | 41 * 43 | 41 * 43
%e . 26 | 1935 | 3^2 * 5 * 43 | 43 * 45
%e . 27 | 2115 | 3^2 * 5 * 47 | 45 * 47
%e . 28 | 2145 | 3 * 5 * 11 * 13 | 11 * 13 * 15
%e . 29 | 2303 | 7^2 * 47 | 47 * 49
%e . 30 | 2499 | 3 * 7^2 * 17 | 49 * 51 .
%o (Haskell)
%o import Data.Set (singleton, deleteFindMin, insert)
%o a257836 n = a257836_list !! (n-1)
%o a257836_list = f $ singleton (15, 3, 5) where
%o f s = y : f (insert (w, u, v') $ insert (w `div` u, u + 2, v') s')
%o where w = y * v'; v' = v + 2
%o ((y, u, v), s') = deleteFindMin s
%Y Cf. A005408, A097889.
%K nonn
%O 1,1
%A _Reinhard Zumkeller_, May 12 2015
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