A373634 Positive integers that cannot be written as a sum of a practical number and a 17-gonal number.

10, 11, 14, 15, 22, 26, 27, 34, 38, 39, 44, 46, 51, 58, 62, 63, 69, 70, 74, 75, 82, 86, 87, 92, 93, 94, 99, 103, 111, 115, 116, 119, 123, 131, 135, 139, 146, 147, 153, 155, 164, 165, 170, 186, 189, 207, 212, 218, 223, 230, 231, 236, 242, 266, 278, 284, 296

Offset

1,1

Comments

Somu and Tran (2024) conjectured that there are finitely many such integers. It was also conjectured that 9314 is the largest such integer. This conjecture was checked up to 10^8.

Links

Duc Van Khanh Tran, Table of n, a(n) for n = 1..106

Sai Teja Somu and Duc Van Khanh Tran, On sums of practical numbers and polygonal numbers, Journal of Integer Sequences, 27(5), 2024.

Crossrefs

Cf. A005153, A051869.

Sequence in context: A085186 A345289 A298365 * A373633 A373665 A373646

Adjacent sequences: A373631 A373632 A373633 * A373635 A373636 A373637

Keyword

nonn,hard

Author

Duc Van Khanh Tran, Jun 11 2024

Status

approved