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A110353 Value of k pertaining to A110351(n). Least k such that the sum (n+1) + (n+2) + ...+(n+k) is a multiple of the n-th triangular number n(n+1)/2.

%I A110353 #7 Dec 05 2013 19:57:01
%S A110353 1,1,5,11,4,8,41,55,26,34,21,27,64,6,65,239,118,134,56,15,56,208,160,
%T A110353 176,274,298,161,175,115,125,929,319,120,50,189,260,628,208,65,575,
%U A110353 204,216,429,55,369,988,657,687,1126,324,221,584,1324,485,120,343,494,1594
%N A110353 Value of k pertaining to A110351(n). Least k such that the sum (n+1) + (n+2) + ...+(n+k) is a multiple of the n-th triangular number n(n+1)/2.
%C A110353 For many values of n, a(n) = A110352(n).
%H A110353 Reinhard Zumkeller, <a href="/A110353/b110353.txt">Table of n, a(n) for n = 1..1000</a>
%o A110353 (Haskell)
%o A110353 import Data.List (findIndex)
%o A110353 import Data.Maybe (fromJust)
%o A110353 a110353 n = (+ 1) $ fromJust $
%o A110353    findIndex ((== 0) . (`mod` t)) $ dropWhile (<= t) a000217_list
%o A110353    where t = a000217 n
%o A110353 -- _Reinhard Zumkeller_, Mar 23 2013
%Y A110353 Cf. A110351, A110352.
%Y A110353 Cf. A000217, A080982.
%K A110353 nonn
%O A110353 1,3
%A A110353 _Amarnath Murthy_, Jul 21 2005
%E A110353 More terms from _Joshua Zucker_, May 08 2006