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A249411 Oblong numbers in A249407.

%I A249411 #4 Nov 01 2014 14:42:54
%S A249411 2,12,30,42,72,110,156,210,272,342,380,420,462,552,650,756,870,992,
%T A249411 1122,1260,1406,1560,1722,1892,2070,2256,2450,2652,2862,3080,3192,
%U A249411 3422,3660,3906,4160,4422,4692,4970,5256,5550,5852,6162,6480,6806,7140,7482,7832
%N A249411 Oblong numbers in A249407.
%C A249411 A005369(a(n)) = 1.
%H A249411 Reinhard Zumkeller, <a href="/A249411/b249411.txt">Table of n, a(n) for n = 1..301</a>
%e A249411 Distribution of oblong numbers on A249406 and its complement,
%e A249411 m*(m+1) factorizations are shown in respective columns:
%e A249411 .   n | A002378 | A249406 | A249407     n | A002378 | A249406 | A249407
%e A249411 .  ---+---------+---------+--------    ---+---------+---------+--------
%e A249411 .   1 |       2 |         |     1*2    13 |     182 |   13*14 |
%e A249411 .   2 |       6 |     2*3 |            14 |     210 |         |   14*15
%e A249411 .   3 |      12 |         |     3*4    15 |     240 |   15*16 |
%e A249411 .   4 |      20 |     4*5 |            16 |     272 |         |   16*17
%e A249411 .   5 |      30 |         |     5*6    17 |     306 |   17*18 |
%e A249411 .   6 |      42 |         |     6*7    18 |     342 |         |   18*19
%e A249411 .   7 |      56 |     7*8 |            19 |     380 |         |   19*20
%e A249411 .   8 |      72 |         |     8*9    20 |     420 |         |   20*21
%e A249411 .   9 |      90 |    9*10 |            21 |     462 |         |   21*22
%e A249411 .  10 |     110 |         |   10*11    22 |     506 |   22*23 |
%e A249411 .  11 |     132 |   11*12 |            23 |     552 |         |   23*24
%e A249411 .  12 |     156 |         |   12*13    24 |     600 |   24*25 |        .
%o A249411 (Haskell)
%o A249411 a249411 n = a249411_list !! (n-1)
%o A249411 a249411_list = filter ((== 1) . a005369) a249407_list
%Y A249411  Cf. A249407, A005369, subsequence of A002378.
%K A249411 nonn
%O A249411 1,1
%A A249411 _Reinhard Zumkeller_, Oct 31 2014