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A374416
a(n) is the number of ways n can be written as a sum of a practical number and two nonagonal numbers.
1
1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 2, 2, 2, 2, 1, 2, 2, 3, 2, 3, 2, 3, 0, 2, 3, 5, 2, 3, 3, 5, 2, 3, 3, 4, 1, 3, 4, 3, 2, 3, 4, 5, 2, 2, 3, 2, 1, 5, 6, 5, 3, 4, 3, 5, 3, 5, 5, 4, 2, 4, 4, 2, 4, 5, 5, 7, 4, 2, 2, 2, 3, 5, 5, 5, 4, 5, 3, 7, 5, 5
OFFSET
1,2
COMMENTS
Somu and Tran (2024) proved that a(n) > 0 for sufficiently large n.
Conjecture (checked up to 10^8): a(n) = 0 if and only if n = 23.
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: A375582 A280314 A080354 * A238529 A374415 A195150
KEYWORD
nonn
AUTHOR
Duc Van Khanh Tran, Jul 08 2024
STATUS
approved