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 1-3 of 3 results.

A195188 Number of decimal digits in n-th ultraprimorial.

Original entry on oeis.org

1, 1, 5, 45, 488, 7770, 134461, 2913994, 67769386, 1862487633, 63473407780, 2266783873440, 95508217654131, 4406526837238776, 210850931948426737, 10938149689908832133, 635914633137982893475, 40923887389117331715131, 2705755577277227205802881
Offset: 0

Views

Author

Kausthub Gudipati, Sep 11 2011

Keywords

Crossrefs

Cf. A165812.

Extensions

More terms from D. S. McNeil, Sep 11 2011

A195529 Ultracompositorial: Compositorials raised to the power of themselves.

Original entry on oeis.org

1, 256, 1333735776850284124449081472843776
Offset: 0

Views

Author

Kausthub Gudipati, Sep 21 2011

Keywords

Comments

Next term (192^192) has 439 digits.

Crossrefs

Programs

Formula

a(n) = A000312(A036691(n)). - Amiram Eldar, Jul 20 2025
a(2) = A114993(2). - R. J. Mathar, Aug 22 2025

Extensions

a(2) corrected by Franklin T. Adams-Watters, Sep 21 2011

A174212 Ultradoublefactorials: a(n) = (n!!)^(n!!).

Original entry on oeis.org

1, 1, 4, 27, 16777216, 437893890380859375, 500702078263459319174537025249570888246709955377400223021257741084821677152403456
Offset: 0

Views

Author

Keywords

Comments

The next term (a(8)) has 993 digits. - Harvey P. Dale, Aug 17 2017

Examples

			For n=4 the doublefactorial is n!! = 4*2 = 8 and a(n) = n!!^n!! = 8^8 = 16777216.
		

Crossrefs

Programs

  • Maple
    P:=proc(i) local a,n; for n from 0 by 1 to i do print(doublefactorial(n)^doublefactorial(n)); od; end: P(10);
  • Mathematica
    udf[n_]:=Module[{c=n!!},c^c]; Array[udf,7,0] (* Harvey P. Dale, Aug 17 2017 *)

Formula

a(n) = A006882(n)^A006882(n).
Sum_{n>=1} 1/a(n) = A134877. - Amiram Eldar, Nov 11 2020
Showing 1-3 of 3 results.