OFFSET
1,1
COMMENTS
Somu and Tran (2024) conjectured that there are finitely many such integers. It was also conjectured that 1612172 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..609
Sai Teja Somu and Duc Van Khanh Tran, On sums of practical numbers and polygonal numbers, Journal of Integer Sequences, 27(5), 2024.
EXAMPLE
11 is in the sequence as 13-gonal numbers below 11 are 0, 1 and both 11-0 and 11-1 are not practical. - David A. Corneth, Jun 11 2024
CROSSREFS
KEYWORD
nonn,hard
AUTHOR
Duc Van Khanh Tran, Jun 11 2024
STATUS
approved