A376941 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.
1, 1, 3, 8, 78, 18826, 848809436, 3078251288697343844, 37949774653961921717972183675013581047, 4221065664206126654046840821317530741151656832301121739091602085731664210467
Offset: 1
Keywords
Examples
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.
Links
- Scott R. Shannon, Table of n, a(n) for n = 1..18