A167277 - OEIS

%I #8 Dec 26 2022 15:23:20

%S 1,22,36,46,52,66,78,82,88,96,112,126,130,156,162,166,172,210,222,232,

%T 250,256,262,276,292,306,316,330,336,352,358,366,372,378,382,388,396,

%U 400,408,438,442,448,456,466,478,486,490,498,502,508,540,546,556,562

%N Largest nonprime<n-th single (or isolated or non-twin) prime.

%C Or, n-th single prime minus smallest divisor of n-th single prime.

%H Harvey P. Dale, <a href="/A167277/b167277.txt">Table of n, a(n) for n = 1..2500</a>

%F a(n) = A007510(n) - 1

%t Select[Prime[Range[150]],NoneTrue[#+{2,-2},PrimeQ]&]-1 (* _Harvey P. Dale_, Dec 26 2022 *)

%K nonn

%O 1,2

%A _Juri-Stepan Gerasimov_, Nov 01 2009

%E Entries checked by _R. J. Mathar_, May 21 2010