Search: id:A105418
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%I A105418
%S A105418 2,0,3,11,53,71,61,191,953,1151,3833,7159,4093,30713,36857,110587,
%T A105418 360439,663547,2064379,786431,3932153,5242877,9437179,63700991,
%U A105418 138412031,169869311,436207613,3875536883,1358954453,1879048183
%N A105418 Smallest prime p such that the sum of it and the following prime have 
               n prime factors including multiplicity, or 0 if no such prime exists.
%C A105418 a(2) = 0 since it is impossible.
%e A105418 a(5) = 53 because (53 + 59) = 112 = 2^4*7.
%e A105418 a(24) = 63700991 because (63700991 + 63700993) = 127401984 = 2^19*3^5.
%e A105418 a(28) = 3875536883 because (3875536883 + 3875536909) = 7751073792 = 2^25*3*7*11.
%e A105418 a(29) = 1358954453 because (1358954453 + 1358954539) = 2717908992 = 2^25*3^4.
%e A105418 a(30) = 1879048183 because (1879048183 + 1879048201) = 3758096384 = 2^29*7.
%t A105418 f[n_] := Plus @@ Flatten[ Table[ #[[2]], {1}] & /@ FactorInteger[n]]; 
               t = Table[0, {40}]; Do[a = f[Prime[n] + Prime[n + 1]]; If[a < 41 
               && t[[a]] == 0, t[[a]] = Prime[n]; Print[{a, Prime[n]}]], {n, 111500000}]; 
               t
%Y A105418 Cf. A071215.
%Y A105418 Sequence in context: A071411 A121065 A077928 this_sequence A135433 A104774 
               A087263
%Y A105418 Adjacent sequences: A105415 A105416 A105417 this_sequence A105419 A105420 
               A105421
%K A105418 nonn
%O A105418 1,1
%A A105418 Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it) and Robert G. Wilson 
               v (rgwv(AT)rgwv.com), Apr 06 2005
%E A105418 a(28)=3875536883 from Ray Chandler (rayjchandler(AT)sbcglobal.net) and 
               Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 10 2005
%E A105418 Edited by Ray Chandler (rayjchandler(AT)sbcglobal.net), Apr 10 2005

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