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%I #13 Sep 08 2022 08:45:32
%S 1,2,8,32,512,2048,32768,131072,2097152,134217728,536870912,
%T 34359738368,549755813888,2199023255552,35184372088832,
%U 2251799813685248,144115188075855872,576460752303423488,36893488147419103232,590295810358705651712,2361183241434822606848,151115727451828646838272
%N a(n) = 2^(prime(n) - 2).
%H G. C. Greubel, <a href="/A135620/b135620.txt">Table of n, a(n) for n = 1..465</a>
%F a(n) = 2^(A000040(n)-2) = 2^(A040976(n)) = 2^A000040(n)/4 = A061286(n)/2.
%t Table[2^(Prime[n] - 2), {n,1,25}] (* _G. C. Greubel_, Oct 23 2016 *)
%o (Magma) [2^(NthPrime(n)-2): n in [1..25]]; // _Vincenzo Librandi_, Oct 23 2016
%o (PARI) a(n) = 2^(prime(n)-2); \\ _Michel Marcus_, Oct 23 2016
%Y Cf. A000040, A040976, A061286.
%Y Partial differences of A135482.
%K easy,nonn
%O 1,2
%A _Omar E. Pol_, Mar 01 2008
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