1,2

Conjecture: A156869(2n + m, n + m) = a(n) if and only if m >= 0.

For n = 2, the a(2) = 4 sequences are (1, 2, 3, 6), (1, 2, 4, 4), (1, 3, 3, 3) and (2, 2, 2, 2) because 1/1 + 1/2 + 1/3 + 1/6 = 1/1 + 1/2 + 1/4 + 1/4 = 1/1 + 1/3 + 1/3 + 1/3 = 1/2 + 1/2 + 1/2 + 1/2 = 2.

a(n) = A156869(2n, n)

Sequence in context: A059837 A054759 A007153 this_sequence A145075 A058924 A154731

Adjacent sequences: A156867 A156868 A156869 this_sequence A156871 A156872 A156873

more,nonn

Jens Voss (jens(AT)voss-ahrensburg.de), Feb 17 2009

a(6) from M. F. Hasler, Feb 21 2009