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 A081467 a(n) = smallest (n+k) such that n divides the sum {(n+1)+ (n+2) + ... (n+k)} or n divides kn + k(k+1)/2. 5

%I

%S 2,5,5,11,9,9,13,23,17,14,21,20,25,21,20,47,33,26,37,35,27,33,45,39,

%T 49,38,53,35,57,45,61,95,44,50,49,44,73,57,51,55,81,62,85,76,54,69,93,

%U 80,97,74,68,91,105,81,65,104,75,86,117,75

%N a(n) = smallest (n+k) such that n divides the sum {(n+1)+ (n+2) + ... (n+k)} or n divides kn + k(k+1)/2.

%e a(4) = 11 as 4 divides 5+6+7+8+9+10+11 and not a smaller sum.

%Y Cf. A081468, A081469, A081470, A081471, A081472.

%K nonn

%O 1,1

%A _Amarnath Murthy_, Mar 23 2003

%E More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 06 2003

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Last modified October 1 17:45 EDT 2020. Contains 337444 sequences. (Running on oeis4.)