A376941 - OEIS

%I #11 Nov 03 2024 09:35:10

%S 1,1,3,8,78,18826,848809436,3078251288697343844,

%T 37949774653961921717972183675013581047,

%U 4221065664206126654046840821317530741151656832301121739091602085731664210467

%N Lexicographically earliest sequence of positive integers a(1), a(2), a(3), ... such that for any n > 0, Sum_{k = 1..n} 1/(k*a(k)) < Sum_{k = 1..oo} 1/k^2 = Pi^2/6.

%H Scott R. Shannon, <a href="/A376941/b376941.txt">Table of n, a(n) for n = 1..18</a>

%e a(7) = 848809436 as Sum_{k = 1..7} 1/(k*a(k)) = 1/(1*1) + 1/(2*1) + ... + 1/(6*18826) + 1/(7*848809436) = 430556991329920237/261747263922187680, which is ~4.1*10^-20 less than Pi^2/6.

%Y Cf. A013661, A376934, A270744, A375781, A375529, A074631, A270752.

%K nonn

%O 1,3

%A _Scott R. Shannon_, Oct 12 2024