A162023 Exactly 10 consecutive odd integers starting with n are composite.

1131, 1341, 1673, 1953, 2183, 2313, 2483, 2559, 2979, 3143, 3231, 3279, 3471, 3741, 3969, 4029, 4181, 4307, 4527, 4763, 4841, 5127, 5241, 5361, 5451, 5537, 5603, 5759, 5961, 6177, 6401, 6429, 6501, 6741, 6927, 7083, 7131, 7263, 7373, 7769, 7797, 7973

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

Exactly 10 consecutive odd integers 1131(2)1149 are composite while 1151 is prime.

Maple

R:= NULL: count:= 0: k:= 1: state:= 0:
while count < 100 do
  k:= k+2;
  if isprime(k) then
    if state >= 10 then R:= R, k - 20; count:= count + 1;  fi;
    state:= 0;
  else state:= state + 1
  fi;
od:
R; # Robert Israel, Feb 12 2025

Mathematica

Transpose[Select[Partition[Range[1, 8001, 2], 11, 1], PrimeQ/@ == {False, False, False, False, False, False, False, False, False, False, True}&]] [[1]] (* Harvey P. Dale, Nov 21 2011 *)

Crossrefs

Cf. A162022, A014076, A071904.

Sequence in context: A163560 A252287 A211684 * A166957 A163651 A122476

Adjacent sequences: A162020 A162021 A162022 * A162024 A162025 A162026

Keyword

nonn

Author

Zak Seidov, Jun 25 2009, typo corrected Aug 14 2009

Status

approved