cp's OEIS Frontend

A159270 Number of positive integers m<=n such that 2^m+3^n or 2^n+3^m is prime.

%I A159270 #26 Aug 06 2022 07:23:51
%S A159270 0,1,2,2,3,3,3,4,5,3,5,3,6,6,4,4,7,6,8,4,4,4,4,6,7,2,4,5,6,6,8,6,10,3,
%T A159270 3,5,6,4,9,6,9,7,5,5,9,6,8,7,7,10,4,5,8,9,1,8,6,6,7,7,10,5,5,4,10,8,7,
%U A159270 8,8,2,3,8,8,8,5,6,7,5,10,6,7,7,8,10,10,9,10,5,7,5,5,6,9,6,5,5,12,3,7,6,8,9
%N A159270 Number of positive integers m<=n such that 2^m+3^n or 2^n+3^m is prime.
%C A159270 Zeros occur at n = 0 and for n in A159625.
%C A159270 For the values in A159625 both A159266(x) and A123359(x) are greater than x. - _Michel Marcus_, Apr 07 2014
%H A159270 Michel Marcus, <a href="/A159270/b159270.txt">Table of n, a(n) for n = 0..2000</a>
%H A159270 David Broadhurst, <a href="https://groups.yahoo.com/neo/groups/primenumbers/conversations/topics/20062">2^m+3^n and 2^n+3^m</a>, Prime numbers and primality testing Group, Apr 11 2009. [Broken link]
%H A159270 Maximilian Hasler, Mike Oakes, Mark Underwood, David Broadhurst and others, <a href="/A159625/a159625.txt">Primes of the form (x+1)^p-x^p</a>, digest of 22 messages in primenumbers Yahoo group, Apr 5 - May 7, 2009. [Cached copy]
%H A159270 Mark Underwood, <a href="https://groups.yahoo.com/neo/groups/primenumbers/conversations/topics/20013">Re: primes of the form (x+1)^p-x^p</a>, Prime numbers and primality testing Group, Apr 07 2009. [Broken link]
%o A159270 (PARI) A159270(n)=sum(m=1,n, ispseudoprime(2^n+3^m) || ispseudoprime(3^n+2^m))
%Y A159270 Cf. A159266, A123359, A159625.
%K A159270 nonn
%O A159270 0,3
%A A159270 _M. F. Hasler_, Apr 09 2009