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A327600 a(n) is the largest k such that the sum of k consecutive reciprocals 1/p_n + ... + 1/p_(n+k-1) does not exceed 1 (where p_n = n-th prime). 0

%I #19 Sep 29 2019 11:34:54

%S 2,8,26,65,143,252,423,650,976,1391,1865,2478,3168,3980,4977,6136,

%T 7419,8828,10476,12278,14294,16612,19123,21905,24903,28055,31493,

%U 35319,39485,44101,49115,54102,59467,65142,71314,77648,84503,91719,99302,107364

%N a(n) is the largest k such that the sum of k consecutive reciprocals 1/p_n + ... + 1/p_(n+k-1) does not exceed 1 (where p_n = n-th prime).

%C The sequence is nondecreasing, since 1/p_n + ... + 1/p_(n+k-1) > 1/p_(n+1) + ... + 1/p_(n+k).

%F a(n) = A137368(n) - 1.

%e For n = 1, since 1/p_1 + 1/p_2 = 1/2 + 1/3 = 5/6 <= 1 while 1/p_1 + 1/p_2 + 1/p_3 = 1/2 + 1/3 + 1/5 = 31/30 > 1, a(1) = 2.

%Y Analog of A136617. Cf. A137368.

%K nonn

%O 1,1

%A _Leon Bykov_, Sep 18 2019

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Last modified April 24 15:42 EDT 2024. Contains 371960 sequences. (Running on oeis4.)