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The (7^n)-th composite number.
0

%I #7 Apr 21 2018 17:36:36

%S 4,14,69,426,2811,18964,129796,894425,6189788,42955634,298658894,

%T 2079246204,14489671674,101048453166,705093892472,4922191483150,

%U 34373676895999,240115703266097,1677722277599685,11724848294191033,81953661525423276,572918021989157017

%N The (7^n)-th composite number.

%t Composite[n_Integer] := Block[ {k = n + PrimePi[n] + 1 }, While[ k != n + PrimePi[k] + 1, k = n + PrimePi[k] + 1]; Return[ k ]]; Table[ Composite[7^n], {n, 0, 16} ]

%K nonn

%O 0,1

%A _Robert G. Wilson v_, Nov 27 2001

%E Corrected and extended by _Chai Wah Wu_, Apr 20 2018