A316857 Heinz numbers of integer partitions whose reciprocal sum is the reciprocal of an integer.

2, 3, 5, 7, 9, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 49, 53, 59, 61, 65, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 125, 127, 131, 137, 139, 147, 149, 151, 157, 163, 167, 169, 173, 179, 181, 191, 193, 195, 197, 199, 211, 223, 227, 229, 233, 239

Offset

1,1

Comments

The reciprocal sum of (y_1, ..., y_k) is 1/y_1 + ... + 1/y_k.

The Heinz number of an integer partition (y_1, ..., y_k) is prime(y_1) * ... * prime(y_k).

Links

Table of n, a(n) for n=1..59.

Mathematica

Select[Range[2, 100], IntegerQ[1/Sum[m[[2]]/PrimePi[m[[1]]], {m, FactorInteger[#]}]]&]

Crossrefs

Cf. A000041, A051908, A056239, A058360, A072411, A296150, A316854, A316855, A316856.

Sequence in context: A326149 A301987 A353393 * A318589 A132630 A033946

Adjacent sequences: A316854 A316855 A316856 * A316858 A316859 A316860

Keyword

nonn

Author

Gus Wiseman, Jul 14 2018

Status

approved