A226644 Number of ways to express 5/n as Egyptian fractions in just three terms; i.e., 5/n = 1/x + 1/y + 1/z satisfying 1<=x<=y<=z.

0, 1, 2, 4, 3, 4, 4, 7, 12, 10, 3, 17, 6, 21, 21, 12, 6, 26, 13, 28, 22, 18, 9, 61, 36, 18, 24, 48, 22, 57, 5, 27, 38, 26, 42, 60, 11, 24, 56, 70, 6, 71, 13, 79, 79, 19, 12, 99, 41, 96, 38, 55, 12, 84, 62, 86, 50, 41, 36, 160, 6, 26, 104, 57, 59, 76, 16, 71, 74, 136, 12, 158, 22, 60, 196, 52, 65, 103, 25, 128, 46, 30, 15, 224, 73, 32, 58, 141, 38, 211, 71, 67, 59, 41, 80, 151, 24, 97, 222, 292

Offset

1,3

Comments

See A073101 for the 4/n conjecture due to Erdős and Straus.

Links

Table of n, a(n) for n=1..100.

Mathematica

f[n_] := Length@ Solve[ 5/n == 1/x + 1/y + 1/z && 1 <= x <= y <= z, {x, y, z}, Integers]; Array[f, 70]

Crossrefs

Cf. A075248, A004194, A226641, A226642, A192787, A226645, A226646.

Sequence in context: A339099 A098604 A274047 * A083172 A287797 A369430

Adjacent sequences: A226641 A226642 A226643 * A226645 A226646 A226647

Keyword

nonn

Author

Allan C. Wechsler and Robert G. Wilson v, Aug 17 2013

Status

approved