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A373610
Positive integers that cannot be written as a sum of a practical number and an octagonal number.
1
11, 15, 34, 35, 47, 59, 103, 110, 115, 122, 123, 142, 146, 154, 159, 167, 179, 195, 203, 207, 214, 239, 247, 251, 262, 287, 290, 311, 318, 319, 323, 339, 354, 355, 362, 394, 434, 447, 466, 538, 542, 563, 599, 627, 682, 707, 718, 739, 743, 759, 774, 782, 867
OFFSET
1,1
COMMENTS
Somu and Tran (2024) conjectured that there are finitely many such integers. It was also conjectured that 4005819 is the largest such integer. This conjecture was checked up to 10^8.
LINKS
Sai Teja Somu and Duc Van Khanh Tran, On sums of practical numbers and polygonal numbers, Journal of Integer Sequences, 27(5), 2024.
CROSSREFS
Sequence in context: A030099 A085597 A316643 * A097512 A032490 A068483
KEYWORD
nonn,hard
AUTHOR
Duc Van Khanh Tran, Jun 10 2024
STATUS
approved