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%I #22 Dec 21 2021 23:46:56
%S 1,1,2,4,4,4,4,4,8,6,6,8,4,4,8,10,6,6,8,4,6,8,8,12,10,4,4,4,4,16,16,8,
%T 6,10,10,6,10,8,8,10,6,10,10,4,4,12,22,14,4,4,8,6,10,14,10,10,6,6,8,4,
%U 10,22,16,4,4,16,18,14,10,4,8,12,12,10,8,8,12,10,10,16,10,10,10,6,8,8
%N Size of sea of composite numbers surrounding n-th prime.
%H T. D. Noe, <a href="/A046930/b046930.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = A031131(n) - 2 for n > 1. - _Reinhard Zumkeller_, Dec 19 2013
%e 23 is in a sea of 8 composites: 20,21,22,23,24,25,26,27,28.
%p [ seq(ithprime(i)-ithprime(i-2)-2,i=3..100) ];
%t Table[ Prime[n + 2] - Prime[n] - 2, {n, 75}] (* _Robert G. Wilson v_ Oct 27 2004 *)
%t Join[{1},#[[3]]-#[[1]]-2&/@Partition[Prime[Range[90]],3,1]] (* _Harvey P. Dale_, Sep 26 2012 *)
%o (Haskell)
%o a046930 1 = 1
%o a046930 n = subtract 2 $ a031131 n -- _Reinhard Zumkeller_, Dec 19 2013
%Y Related sequences: A023186-A023188, A046929-A046931, A051650, A051652, A051697-A051702, A051728-A051730.
%K nonn,easy,nice
%O 1,3
%A _N. J. A. Sloane_, _Marc LeBrun_
%E More terms from _Michel ten Voorde_
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