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%I #18 Jul 31 2017 12:43:11
%S 2,6,10,12,18,24,26,28,48,66,70,72,78,80,82,84,90,108,110,114,120,130,
%T 132,140,156,170,174,182,190,192,222,234,238,242,252,255,258,264,276,
%U 280,290,294,306,308,310,318,336,342,350,354,366,372,374,378,380,396,402,408,410,418
%N Numbers n such that omega(n-1) + omega(n+1) = omega(n) where omega(n) = A001221(n).
%H Charles R Greathouse IV, <a href="/A190789/b190789.txt">Table of n, a(n) for n = 1..10000</a>
%F omega(a(n)-1) + omega(a(n)+1) = omega(a(n)).
%e a(35)=255 because omega(254)+omega(256)=omega(255) or 2+1=3.
%t Select[Range[5000], PrimeNu[# - 1] + PrimeNu[# + 1] == PrimeNu[ #] &] (* _G. C. Greubel_, Apr 24 2017 *)
%t Flatten[Position[Partition[PrimeNu[Range[450]],3,1],_?(#[[1]]+#[[3]] == #[[2]]&),1,Heads->False]]+1 (* _Harvey P. Dale_, Jul 31 2017 *)
%o (PARI) isok(n) = omega(n) == omega(n-1) + omega(n+1); \\ _Michel Marcus_, Apr 25 2017
%Y Cf. A001221.
%K nonn,easy
%O 1,1
%A _Juri-Stepan Gerasimov_, May 19 2011
%E a(18) corrected, a(22) added by _Charles R Greathouse IV_, May 24 2011