A317399 Positive integers that have exactly nine representations of the form 1 + p1 * (1 + p2* ... * (1 + p_j)...), where [p1, ..., p_j] is a (possibly empty) list of distinct primes.

7021, 7162, 8053, 8737, 9178, 9556, 10126, 10858, 10861, 10866, 11113, 11133, 11363, 11740, 12076, 12111, 12666, 13168, 13210, 13339, 13573, 13729, 14037, 14366, 14411, 14691, 15250, 15478, 15569, 15653, 15726, 15922, 16066, 16113, 16116, 16386, 16459, 16644

Offset

1,1

Links

Alois P. Heinz, Table of n, a(n) for n = 1..20000

Formula

A317241(a(n)) = 9.

Maple

b:= proc(n, s) option remember; local p, r; if n=1 then 1 else r:=0;
      for p in numtheory[factorset](n-1) minus s while r<10
        do r:= r+b((n-1)/p, s union {p}) od; `if`(r<10, r, 10)
      fi
    end:
a:= proc(n) option remember; local k; for k from
     `if`(n=1, 1, 1+a(n-1)) while b(k, {})<>9 do od; k
    end:
seq(a(n), n=1..100);

Crossrefs

Column k=9 of A317390.

Cf. A317241.

Sequence in context: A100897 A206757 A236061 * A116278 A206050 A116332

Adjacent sequences: A317396 A317397 A317398 * A317400 A317401 A317402

Keyword

nonn

Author

Alois P. Heinz, Jul 27 2018

Status

approved