A348625 Number of Egyptian fractions with squared denominators: number of solutions to the equation 1 = 1/x_1^2 + ... + 1/x_n^2 with 0 < x_1 <= ... <= x_n.

1, 0, 0, 1, 0, 1, 1, 4, 7, 47, 186, 1809, 27883

Offset

1,8

Comments

All denominators are bounded by A348626(n), i.e., 0 < x_1 <= ... <= x_n < A348626(n). Furthermore, for a fixed n, x_i <= sqrt(n+1-i)*(A348626(i)-1).

Links

Table of n, a(n) for n=1..13.

Crossrefs

Cf. A002966, A348626.

Sequence in context: A139030 A115439 A375381 * A192168 A094609 A249936

Adjacent sequences: A348622 A348623 A348624 * A348626 A348627 A348628

Keyword

nonn,hard,more

Author

Max Alekseyev, Oct 25 2021

Status

approved