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A347568
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Positive integers which are not twice a positive triangular number and cannot be written as twice a positive triangular number plus an odd prime or twice a positive triangular number plus twice an odd prime.
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1
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OFFSET
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1,2
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COMMENTS
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Probably finite. No more terms < 10^9.
Asked by an anonymous person on Wikipedia, December 31 2021.
No more terms < 10^11. - Martin Ehrenstein, Jan 15 2022
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LINKS
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Table of n, a(n) for n=1..8.
Wikipedia:Reference desk/Mathematics, Original question on Wikipedia December 31 2021
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EXAMPLE
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5 is NOT a term because 5 is not twice a triangular number and it can be written as 2*1+3, where 1 is a triangular and 3 is an odd prime. However, 10 is a term because it cannot be written in this way.
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CROSSREFS
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Cf. A000040, A000217, A347567.
Sequence in context: A056517 A285042 A319719 * A048155 A242342 A204292
Adjacent sequences: A347565 A347566 A347567 * A347569 A347570 A347571
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KEYWORD
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nonn,more
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AUTHOR
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Jud McCranie, Jan 02 2022
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STATUS
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approved
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