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.

Showing 1-2 of 2 results.

A136156 Quotients p!/n arising in A139171.

Original entry on oeis.org

2, 1, 2, 30, 24, 1, 720, 15, 560, 12, 3628800, 10, 479001600, 360, 8, 315, 20922789888000, 280, 6402373705728000, 6, 240, 1814400, 1124000727777607680000, 5, 1596672, 239500800, 1478400, 180, 304888344611713860501504000000, 4, 265252859812191058636308480000000
Offset: 1

Views

Author

N. J. A. Sloane, Apr 13 2008

Keywords

Programs

  • Mathematica
    f[n_] := Block[{m = 1}, While[ !IntegerQ[ Prime@ m!/n], m++ ]; Prime@ m!/n]; Array[f, 31] (* Robert G. Wilson v, Apr 17 2008 *)

Extensions

More terms from Robert G. Wilson v, Apr 17 2008

A139169 a(n)=smallest k >= 1 such that n divides prime(k)!.

Original entry on oeis.org

1, 1, 2, 3, 3, 2, 4, 3, 4, 3, 5, 3, 6, 4, 3, 4, 7, 4, 8, 3, 4, 5, 9, 3, 5, 6, 5, 4, 10, 3, 11, 5, 5, 7, 4, 4, 12, 8, 6, 3, 13, 4, 14, 5, 4, 9, 15, 4, 7, 5, 7, 6, 16, 5, 5, 4, 8, 10, 17, 3, 18, 11, 4, 5, 6, 5, 19, 7, 9, 4, 20, 4, 21, 12, 5, 8, 5, 6, 22, 4, 5, 13, 23, 4, 7, 14, 10, 5, 24, 4, 6, 9, 11, 15
Offset: 1

Views

Author

Artur Jasinski, Apr 11 2008

Keywords

Links

Crossrefs

Indices of primes in A139171.
Cf. A082672, A089085, A089130, A117141, A007749, A139056-A139066, A139068, A137390, A139070-A139075, A139148-A139157, A139159, A139160-A139166, A139089, A139168-A139170.

Programs

  • Maple
    f:= proc(n) local F,m,Q,E,p;
  F:= ifactors(n)[2];
  m:= nops(F);
  Q:= map(t -> t[1],F);
  E:= map(t -> t[2],F);
  p:= max(Q)-1;
  do
    p:= nextprime(p);
    if andmap(i -> add(floor(p/Q[i]^j),j=1..floor(log[Q[i]](p))) >= E[i], [$1..m]) then return p fi;
  od
end proc:
f(1):= 2:
map(numtheory:-pi @ f, [$1..100]); # Robert Israel, Mar 07 2018
  • Mathematica
    a = {}; Do[m = 1; While[ ! IntegerQ[Prime[m]!/n], m++ ]; AppendTo[a, m], {n, 1, 100}]; a
  • PARI
    a(n) = forprime(p=2,, if (!(p! % n), return (primepi(p)))); \\ Michel Marcus, Mar 08 2018
Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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