cp's OEIS Frontend

A060064 First subsequent, disjoint occurrence of n consecutive nonprimes.

%I A060064 #19 May 05 2025 23:17:16
%S A060064 4,8,14,24,32,90,114,140,182,200,212,294,318,524,888,1070,1130,1328,
%T A060064 1638,1670,1952,2180,2478,2972,3138,3272,4298,4832,5352,5592,8468,
%U A060064 9552,9974,12854,14108,15684,16142,19334,19610,25472,28230,31398,31908,34062
%N A060064 First subsequent, disjoint occurrence of n consecutive nonprimes.
%C A060064 Conjecture: a(n) - 1 is always prime. - _Robert Israel_, May 04 2025
%H A060064 Robert Israel, <a href="/A060064/b060064.txt">Table of n, a(n) for n = 1..200</a>
%e A060064 First occurrence of 1 consecutive nonprime gives 4, first occurrence of 2 consecutive nonprimes gives 8 and 9, the first subsequent and disjoint occurrence of 3 consecutive nonprimes gives 14, 15 and 16, etc.
%p A060064 P:= select(isprime, [seq(i,i=3..10^8,2)]):
%p A060064 G:= P[2..-1]-P[1..-2]:
%p A060064 R:= NULL: g:= 1:
%p A060064 for i from 1 to nops(G) do
%p A060064  gi:= G[i]; ri:= P[i]+1;
%p A060064  while gi > g do
%p A060064    R:= R, ri;
%p A060064    ri:= ri + g;
%p A060064    gi:= gi - g;
%p A060064    g:= g+1;
%p A060064  od;
%p A060064 od:
%p A060064 R; # _Robert Israel_, May 04 2025
%Y A060064 Cf. A060299, A030296.
%K A060064 nonn
%O A060064 1,1
%A A060064 _Jason Earls_, Mar 25 2001
%E A060064 Better description and more terms from Larry Reeves (larryr(AT)acm.org), Apr 02 2001
%E A060064 Further terms from _Michel ten Voorde_ Apr 10 2001
%E A060064 Missing a(16)=1070 inserted by _Sean A. Irvine_, Oct 21 2022