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%I #14 Dec 18 2019 04:05:59
%S 3,10,21,34,51,80,103,146,187,260,319,366,455,522,595,702,791,892,
%T 1019,1116,1199,1288,1385,1636,1767,1880,2031,2294,2545,2768,2947,
%U 3336,3617,3768,3965,4138,4377,4610,4801,5024,5247,5540,6133,6426,6883,7110,7421
%N a(n) = Sum_{i=2..n} A055211(i).
%F Let F(n) := a(n)/A007504(n). Conjecture: as n tends to infinity F(n) tends to Pi/2 with Pi=3.14159......
%t PrevPrime[ n_Integer] := Block[ {k = n - 1}, While[ ! PrimeQ[ k ], k-- ]; k ]; LF[ n_Integer ] := Block[ { p = Product[ Prime[ i ], {i, 1, n} ] - 1, q}, q = PrevPrime[ p ]; p - q + 1 ]; t = Table[LF[ n ], {n, 2, 48}]; Table[Plus @@ Take[t, n], {n, 47}] (* _Robert G. Wilson v_, Sep 04 2004 *)
%Y Cf. A007504, A055211.
%K nonn
%O 2,1
%A _Pierre CAMI_, Aug 29 2004
%E More terms from _Robert G. Wilson v_, Sep 04 2004