cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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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.

Original entry on oeis.org

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

Views

Author

Alois P. Heinz, Jul 27 2018

Keywords

Crossrefs

Column k=9 of A317390.
Cf. A317241.

Programs

  • 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);

Formula

A317241(a(n)) = 9.

A317400 Positive integers that have exactly ten representations of the form 1 + p1 * (1 + p2* ... * (1 + p_j)...), where [p1, ..., p_j] is a (possibly empty) list of distinct primes.

Original entry on oeis.org

11306, 13289, 13693, 16402, 16446, 16491, 16699, 17031, 17113, 17116, 17263, 17576, 18412, 18602, 19825, 20023, 20411, 21022, 21256, 21676, 21936, 22271, 22543, 22716, 22764, 23038, 23233, 23332, 23353, 23580, 23599, 23886, 24036, 24053, 24064, 24531, 24646
Offset: 1

Views

Author

Alois P. Heinz, Jul 27 2018

Keywords

Crossrefs

Column k=10 of A317390.
Cf. A317241.

Programs

  • 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<11
            do r:= r+b((n-1)/p, s union {p}) od; `if`(r<11, r, 11)
          fi
        end:
    a:= proc(n) option remember; local k; for k from
         `if`(n=1, 1, 1+a(n-1)) while b(k, {})<>10 do od; k
        end:
    seq(a(n), n=1..100);

Formula

A317241(a(n)) = 10.

A317537 The n-th positive integer that has exactly n representations of the form 1 + p1 * (1 + p2* ... * (1 + p_j)...), where [p1, ..., p_j] is a (possibly empty) list of distinct primes.

Original entry on oeis.org

1, 29, 91, 426, 1002, 2283, 3979, 5886, 10861, 17116, 20749, 35106, 44031, 60919, 67453, 108655, 142429, 197107, 232625, 303317, 352093, 432517, 542935, 642520, 839938, 988791, 1050505, 1208559, 1612876, 1753324, 2129203, 2391496, 2735890, 3141916, 3593278
Offset: 1

Views

Author

Alois P. Heinz, Jul 30 2018

Keywords

Examples

			a(1) = 1: 1.
a(2) = 29: 1 + 2 * (1 + 13) = 1 + 7 * (1 + 3) = 29.
a(3) = 91: 1 + 2 * (1 + 11 * (1 + 3)) = 1 + 3 * (1 + 29) = 1 + 5 * (1 + 17) = 91.
		

Crossrefs

A diagonal of A317390.
Cf. A317385.

Formula

a(n) = A317390(n,n).
Previous Showing 11-13 of 13 results.