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A347568 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. 1

%I

%S 1,3,4,10,14,122,422,432

%N 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.

%C Probably finite. No more terms < 10^9.

%C Asked by an anonymous person on Wikipedia, December 31 2021.

%C No more terms < 10^11. - _Martin Ehrenstein_, Jan 15 2022

%H Wikipedia:Reference desk/Mathematics, <a href="https://en.wikipedia.org/wiki/Wikipedia:Reference_desk/Archives/Mathematics/2021_December_31#Number_theory">Original question on Wikipedia December 31 2021</a>

%e 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.

%Y Cf. A000040, A000217, A347567.

%K nonn,more

%O 1,2

%A _Jud McCranie_, Jan 02 2022

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Last modified August 14 05:20 EDT 2022. Contains 356110 sequences. (Running on oeis4.)