A270429 Minimal total number of unit fractions required to sum up all fractions 1/n, 2/n, ..., n/n.

1, 2, 4, 5, 9, 8, 15, 13, 17, 18, 28, 19, 34, 30, 31, 33, 48, 34, 54, 39, 47, 56, 69, 45, 67, 68, 67, 63, 91, 62, 97, 77, 88, 96, 91, 75, 121, 108, 106, 89, 137, 94, 144, 115, 111, 138, 159, 105, 149, 134, 147, 141, 181, 134, 155, 139, 168, 182, 205, 131

Offset

1,2

Links

Table of n, a(n) for n=1..60.

Formula

a(n) = Sum_{k=1..n} A097847(n,k). - Alois P. Heinz, Jul 12 2016

Example

For n = 3: 1/3 and 3/3 = 1/1 are unit fractions themselves. 2/3 can be generated as the sum of two unit fractions: 1/2 + 1/6. This gives us a(3) = 1 + 2 + 1 = 4.

Crossrefs

Row sums of A097847.

Sequence in context: A116477 A116920 A116919 * A359878 A270097 A167511

Adjacent sequences: A270426 A270427 A270428 * A270430 A270431 A270432

Keyword

nonn

Author

Carsten Peust, Jul 12 2016

Status

approved