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 A167428 Smallest non-isolated (or twin) prime > n-th non-isolated nonprime. 1
 3, 3, 11, 11, 11, 17, 17, 17, 29, 29, 29, 29, 29, 29, 29, 29, 41, 41, 41, 41, 41, 41, 41, 41, 59, 59, 59, 59, 59, 59, 59, 59, 59, 59, 59, 59, 59, 71, 71, 71, 71, 71, 71, 71, 71, 101, 101, 101, 101, 101, 101, 101, 101, 101, 101, 101, 101, 101, 101, 101, 101, 101, 101, 101 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE a(1)=3 (>0); a(2)=3 (>1); a(3)=11 (>8); a(4)=11 (>8); a(5)=11 (>10); a(6)=17 (>14). MAPLE A164276 := proc(n) option remember; if n = 1 then 0; else for a from procname(n-1)+1 do if isA164276(a) then return a; end if; end do; end if: end proc: isA164276 := proc(n) not isprime(n) and ( not isprime(n+1) or not isprime(n-1) ) ; end proc: isA001097 := proc(n) isprime(n) and ( isprime(n+2) or isprime(n-2) ); end proc: A167428 := proc(n) for a from A164276(n)+1 do if isA001097(a) then return a; end if; end do: end proc: seq(A167428(n), n=1..120) ; # R. J. Mathar, May 30 2010 CROSSREFS Cf. A001097, A164276. Sequence in context: A122167 A095019 A321082 * A318961 A309798 A068594 Adjacent sequences:  A167425 A167426 A167427 * A167429 A167430 A167431 KEYWORD nonn AUTHOR Juri-Stepan Gerasimov, Nov 03 2009 EXTENSIONS Entries checked by R. J. Mathar, May 30 2010 STATUS approved

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Last modified May 21 09:30 EDT 2022. Contains 353908 sequences. (Running on oeis4.)