A226642 Number of ways to express 3/n as Egyptian fractions in just three terms; i.e., 3/n = 1/x + 1/y + 1/z satisfying 1<=x<=y<=z.

1, 3, 3, 6, 10, 10, 9, 20, 21, 21, 16, 28, 11, 33, 36, 31, 24, 57, 11, 68, 42, 35, 23, 70, 37, 51, 79, 76, 30, 96, 17, 65, 62, 50, 138, 160, 18, 51, 59, 142, 34, 136, 24, 140, 196, 46, 32, 128, 43, 98, 73, 111, 46, 211, 111, 192, 80, 63, 46, 292, 24, 81, 245

Offset

1,2

Comments

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

Links

Table of n, a(n) for n=1..63.

Mathematica

f[n_] := Length@ Solve[ 3/n == 1/x + 1/y + 1/z && 1 <= x <= y <= z, {x, y, z}, Integers]; Array[f, 70]

Crossrefs

Cf. A075785, A004194, A226641, A192787, A226644, A226645, A226646.

Sequence in context: A205004 A236345 A212991 * A266137 A265506 A366317

Adjacent sequences: A226639 A226640 A226641 * A226643 A226644 A226645

Keyword

nonn

Author

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

Status

approved