A378269 Number of partitions of 1 into {1/1, 1/3, 1/5, ..., 1/(2*n-1)}.

1, 2, 3, 4, 7, 8, 9, 28, 29, 30, 90, 91, 150, 294, 295, 296, 659, 2818, 2819, 4815, 4816, 4817, 26648, 26649, 38880, 55745, 55746, 247660, 322628, 322629, 322630, 1942493, 7597991, 7597992

Offset

1,2

Links

Table of n, a(n) for n=1..34.

Index entries for sequences related to Egyptian fractions

Formula

If 2*n-1 is prime, then a(n) = a(n-1) + 1. - Chai Wah Wu, Dec 26 2024

Example

a(5) = 7 because we have 9 * (1/9) = 6 * (1/9) + 1/3 = 3 * (1/9) + 2 * (1/3) = 7 * (1/7) = 5 * (1/5) = 3 * (1/3) = 1.

Crossrefs

Cf. A005408, A020473, A038034.

Sequence in context: A111116 A113318 A056033 * A302123 A381922 A286337

Adjacent sequences: A378266 A378267 A378268 * A378270 A378271 A378272

Keyword

nonn,more

Author

Ilya Gutkovskiy, Nov 21 2024

Extensions

a(20)-a(34) from Jinyuan Wang, Dec 11 2024

Status

approved