A377205 Lexicographically earliest sequence of positive integers a(1), a(2), ... such that for any n >= 0, s(n) = Sum_{k=1..n} 1/(k^2*a(k)) < 1.

2, 1, 1, 1, 1, 1, 3, 9, 171, 122014, 17661589931, 412924014578486602517, 1248808068140660770289141544749321839183623, 4529027355107615424925871833487047912228337079416162414871862143803627237910792872226

Offset

1,1

Links

Alois P. Heinz, Table of n, a(n) for n = 1..17

Example

s(0), s(1), ... = 0, 1/2, 3/4, 31/36, 133/144, 3469/3600, 3569/3600, ... .

Maple

s:= proc(n) option remember; `if`(n=0, 0, s(n-1)+1/(n^2*a(n))) end:
a:= proc(n) option remember; 1+floor(1/((1-s(n-1))*n^2)) end:
seq(a(n), n=1..14);

Crossrefs

Cf. A000290, A013661, A374663, A377229, A377230.

Sequence in context: A305297 A218220 A247487 * A010248 A325403 A132068

Adjacent sequences: A377202 A377203 A377204 * A377206 A377207 A377208

Keyword

nonn

Author

Alois P. Heinz, Oct 19 2024

Status

approved