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A317395 Positive integers that have exactly five representations of the form 1 + p1 * (1 + p2* ... * (1 + p_j)...), where [p1, ..., p_j] is a (possibly empty) list of distinct primes. 2
638, 848, 921, 969, 1002, 1026, 1106, 1156, 1191, 1248, 1276, 1310, 1326, 1341, 1431, 1444, 1480, 1499, 1548, 1592, 1641, 1730, 1764, 1772, 1786, 1856, 1888, 1911, 1996, 2005, 2025, 2038, 2050, 2053, 2061, 2121, 2129, 2131, 2133, 2146, 2171, 2224, 2256, 2258 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

A317241(a(n)) = 5.

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<6

        do r:= r+b((n-1)/p, s union {p}) od; `if`(r<6, r, 6)

      fi

    end:

a:= proc(n) option remember; local k; for k from

     `if`(n=1, 1, 1+a(n-1)) while b(k, {})<>5 do od; k

    end:

seq(a(n), n=1..100);

CROSSREFS

Column k=5 of A317390.

Cf. A317241.

Sequence in context: A203880 A250465 A203879 * A212399 A264449 A210883

Adjacent sequences:  A317392 A317393 A317394 * A317396 A317397 A317398

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Jul 27 2018

STATUS

approved

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Last modified May 27 16:48 EDT 2022. Contains 354110 sequences. (Running on oeis4.)