A246785 a(n) is the least m>0 such that A182134(n - m) = m, or zero if there is no such m.

1, 1, 1, 1, 0, 2, 2, 1, 0, 2, 2, 2, 0, 3, 2, 2, 0, 3, 0, 3, 0, 3, 2, 2, 0, 0, 4, 0, 2, 2, 2, 0, 3, 0, 4, 3, 0, 4, 4, 4, 3, 0, 4, 0, 4, 2, 2, 0, 0, 4, 0, 5, 4, 4, 3, 0, 0, 5, 0, 5, 3, 2, 0, 0, 4, 4, 2, 0, 0, 0, 5

Offset

2,6

Comments

Recall that A182134(k) is the number of primes p with prime(k) < p < prime(k)^(1+1/k). The record values up to n = 56000 are the positive integers up to 21 except 13 which first occurs after 14; A246790 gives indices of these record values.

Links

Robert Price, Table of n, a(n) for n = 2..10000

Mathematica

h[n_]:= If[n==0, 0, (i=Prime[n]+1; j=Prime[n]^(1+1/n); Length[Select[Range[i, j], PrimeQ]])]; a1[n_]:= (For[m=1, m<=n-1 && h[n-m]!= m, m++]; m); a[k_]:= If[c=a1[k]; c==k, 0, c]; Table[a[k], {k, 2, 90}]

Prog

(Haskell)
a246785 n = if null ms then 0 else head ms
            where ms = [m | m <- [1 .. n-1], a182134 (n - m) == m]
-- Reinhard Zumkeller, Nov 17 2014

Crossrefs

Cf. A000040, A182134, A246790, A246793.

Sequence in context: A284387 A143667 A299485 * A084934 A125927 A285864

Adjacent sequences: A246782 A246783 A246784 * A246786 A246787 A246788

Keyword

nonn

Author

Farideh Firoozbakht, Oct 24 2014

Status

approved