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%I #22 Nov 16 2024 18:48:50
%S 2,13,71,263,827,2377,6379,16603,41611,101573,243473,573637,1333613,
%T 3065983,6975971,15746347,35277211,78510373,173717329,382404863,
%U 837870343,1828047503,3973066781,8604768101,18576139177,39983413319
%N a(n) = prime(2^(n-1)*(2*n-1)), n >= 1.
%F a(n) = A000040(2^(n-1)*(2*n-1)).
%F a(n) = A000040(A014480(n-1)). - _Michel Marcus_, Nov 23 2015
%t Table[Prime[2^(n - 1)*(2*n - 1)], {n, 26}]
%o (Magma) [NthPrime(2^(n-1)*(2*n-1)): n in [1..20]]; // _Vincenzo Librandi_, Nov 23 2015
%o (PARI) a(n)=if(n<1,print1("Error n < 1"),prime(2^(n-1)*(2*n-1))) \\ _Anders Hellström_, Nov 23 2015
%o (Perl) use ntheory ":all"; say "$_ ",nth_prime(2**($_-1) * (2*$_-1)) for 1..50; # _Dana Jacobsen_, Apr 28 2017
%Y Cf. A000040, A014480, A264731 (main diagonal).
%K nonn
%O 1,1
%A _L. Edson Jeffery_, Nov 22 2015