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A054690 n consecutive primes differ by 4 or more starting at a(n), or n consecutive primes with no twin primes. 2
7, 19, 43, 73, 73, 349, 349, 349, 349, 349, 349, 661, 661, 661, 661, 661, 661, 661, 661, 8629, 8629, 8629, 8629, 13399, 13399, 13399, 14629, 14629, 24421, 24421, 24421, 24421, 24421, 24421, 24421, 24421, 24421, 24421, 24421, 24421, 24421 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

LINKS

Robert Israel, Table of n, a(n) for n = 2..204

MAPLE

P:= select(isprime, [seq(i, i=3..10^7, 2)]):

A:= 'A':

state:= 0: smax := 0:

for i from 2 to nops(P) do

  if P[i] - P[i-1] >= 4 then

    state:= state + 1;

    if state > smax then smax:= state; A[state+1]:= P[i-state] fi

  else

    state:= 0;

  fi

od:

seq(A[i], i=2..smax+1); # Robert Israel, Jun 27 2017

MATHEMATICA

Prime[#]&/@With[{pd=If[#>2, 1, 0]&/@Differences[Prime[Range[3000]]]}, Flatten[ Table[ SequencePosition[pd, PadRight[{}, n, 1], 1][[All, 1]], {n, 45}]]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 29 2018 *)

CROSSREFS

Cf. A054691, A054692.

Sequence in context: A104163 A145993 A265676 * A259486 A298034 A054691

Adjacent sequences:  A054687 A054688 A054689 * A054691 A054692 A054693

KEYWORD

nonn

AUTHOR

Jeff Burch, Apr 19 2000

STATUS

approved

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Last modified July 30 07:58 EDT 2021. Contains 346348 sequences. (Running on oeis4.)