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A263455 Values k in A084697. 3
1, 1, 2, 2, 2, 2, 6, 3, 8, 2, 12, 3, 4, 1, 2, 1, 4, 3, 4, 4, 6, 4, 4, 1, 4, 1, 4, 4, 4, 1, 10, 4, 2, 6, 2, 1, 2, 2, 2, 3, 22, 2, 10, 1, 8, 10, 4, 5, 6, 2, 4, 2, 2, 1, 2, 5, 6, 2, 12, 1, 4, 1, 8, 3, 2, 3, 2, 11, 8, 2, 2, 2, 8, 3, 2, 1, 4, 2, 16, 4, 6, 3, 6, 1, 10, 1, 10, 3, 18, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Is the sequence unbounded?  We know that k exists for any n but is the value of k unbounded?

LINKS

Zak Seidov, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = (A084697(n+1) - A084697(n))/n.

MAPLE

a[1]:= 2: a[2]:= 3:b[1]:= 1: b[2]:= 1:

for n from 2 to 1000 do

  if n::odd then delta:= 2*n

  else delta:= n

  fi:

    for q from a[n] + delta by delta while not isprime(q) do od:

    a[n+1]:= q:

    b[n]:= (q - a[n])/n;

od:

seq(b[n], n=1..1000); # Robert Israel, Oct 26 2015

MATHEMATICA

a=2; Table[k=1; While[!PrimeQ[b=a+k*n], k++]; a=b; k, {n, 1000}]

PROG

(PARI) lista(nn) = {a = 2; for (n=1, nn, k=1; while (!isprime(na=a+k*n), k++); print1(k, ", "); a = na; ); } \\ Michel Marcus, Oct 21 2015

CROSSREFS

Cf. A084697.

Sequence in context: A293221 A334512 A096625 * A283677 A260983 A103222

Adjacent sequences:  A263452 A263453 A263454 * A263456 A263457 A263458

KEYWORD

nonn

AUTHOR

Zak Seidov, Oct 18 2015

STATUS

approved

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Last modified July 7 23:03 EDT 2020. Contains 335502 sequences. (Running on oeis4.)