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A141560 Nonprimes of form (prime(n)-r(n)), where A141468(n)=r(n)=n-th nonprime and prime(n)=n-th prime. 0

%I #16 Feb 19 2021 08:24:31

%S 1,1,4,9,14,15,21,22,25,34,35,40,50,55,62,65,65,68,69,86,91,91,100,

%T 106,111,118,123,124,133,133,135,136,147,158,161,161,164,169,169,177,

%U 182,187,192,200,201,209,222,225,226,246,255,256,259,264,275,280,287,296

%N Nonprimes of form (prime(n)-r(n)), where A141468(n)=r(n)=n-th nonprime and prime(n)=n-th prime.

%t Module[{nn=200,np,len},np=Select[Range[0,nn],!PrimeQ[#]&];len= Length[ np];Select[ #[[1]]-#[[2]]&/@Thread[{Prime[Range[len]],np}],!PrimeQ[ #]&]] (* _Harvey P. Dale_, Oct 15 2020 *)

%Y Cf. A000040, A141468.

%K nonn,less

%O 1,3

%A _Juri-Stepan Gerasimov_, Aug 14 2008

%E Edited, corrected and extended by _Ray Chandler_, Aug 19 2008

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Last modified April 18 04:56 EDT 2024. Contains 371767 sequences. (Running on oeis4.)