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 1-4 of 4 results.

A004002 Benford numbers: a(n) = e^e^...^e (n times) rounded to nearest integer.

Original entry on oeis.org

1, 3, 15, 3814279
Offset: 0

Views

Author

N. J. A. Sloane

Keywords

Comments

The next term, a(4) ~ 2.3315*10^1656520, has 1656521 decimal digits and is therefore too large to be included. [Rephrased by M. F. Hasler, May 01 2013]
Named by Turner (1991) after the American electrical engineer and physicist Frank Albert Benford, Jr. (1883-1948). - Amiram Eldar, Jun 26 2021

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Crossrefs

Cf. A056072, A225053.
Cf. A073236. - Melissa O'Neill, Jul 04 2015

Programs

  • Maple
    p:= n-> `if`(n=0, 1, exp(1)^p(n-1)):
a:= n-> round(p(n)):
seq(a(n), n=0..3);  # Alois P. Heinz, Jul 20 2024
  • Mathematica
    Round[NestList[Power[E, #] &, 1, 3]] (* Melissa O'Neill, Jul 04 2015 *)

Formula

a(n) = round(e^e^...^e), where e occurs n times, a(0) = 1 (= e^0). - Melissa O'Neill, Jul 04 2015

A056072 a(n) = floor(e^e^ ... ^e), with n e's.

Original entry on oeis.org

1, 2, 15, 3814279
Offset: 0

Views

Author

Robert G. Wilson v, Jul 26 2000

Keywords

Comments

The next term is too large to include.
From Vladimir Reshetnikov, Apr 27 2013: (Start)
a(4) = 2331504399007195462289689911...2579139884667434294745087021 (1656521 decimal digits in total), given by initial segment of A085667.
a(5) has more than 10^10^6 decimal digits.
a(6) has more than 10^10^10^6 decimal digits. (End)

Crossrefs

Cf. A001113, A004002, A003417, A064107, A159825, A073226, A073227, A085667, A096232, A225064, A225053.

Programs

A116692 Primes with only one distinct decimal digit. Also called repunit primes or repdigit primes.

Original entry on oeis.org

2, 3, 5, 7, 11, 1111111111111111111, 11111111111111111111111
Offset: 1

Views

Author

Rick L. Shepherd, Feb 22 2006

Keywords

Comments

Primes in A010785 (repdigit numbers). Union of single-digit primes and A004022 (repunit primes). A004023 shows that the next term has 317 1's. The Mersenne primes (A000668) are the binary analog (i.e., bits are all 1's).

References

  • Clifford A. Pickover, A Passion for Mathematics (2005) at 60, 297.

Crossrefs

A004022 is a subsequence.
Cf. A004023, A010785, A000668.
A subsequence of A055387, but not of A225053.

Extensions

Reference provided by Harvey P. Dale, Apr 19 2014
Definition expanded by N. J. A. Sloane, Jan 22 2023

A221566 Decimal expansion of b^b^b^..., where b equals e-2 (A001113).

Original entry on oeis.org

7, 7, 4, 0, 4, 4, 3, 7, 6, 2, 4, 2, 1, 4, 8, 8, 5, 5, 5, 9, 6, 1, 7, 4, 2, 6, 7, 9, 2, 3, 1, 2, 5, 9, 3, 5, 5, 2, 5, 5, 2, 5, 6, 9, 4, 6, 6, 6, 0, 3, 9, 7, 7, 9, 2, 4, 1, 8, 9, 5, 0, 3, 5, 5, 5, 3, 6, 0, 8, 9, 2, 3, 9, 5, 0, 1, 3, 0, 5, 7, 9, 2, 4, 7, 8, 6, 8, 7, 0, 0, 9, 5, 0, 0, 5, 8, 7, 4, 9, 5, 8, 1, 3, 5, 8
Offset: 0

Views

Author

Vladimir Reshetnikov and Robert G. Wilson v, May 05 2013

Keywords

Comments

Inspired by A225053.

Examples

			0.7740443762421488555961742679231259355255256946660397792418950355...

Crossrefs

Cf. A225053.

Programs

  • Mathematica
    b = N[E - 2, 128]; f[n_] := Nest[b^# &, b, n]; RealDigits[ f[186], 10, 111][[1]]
RealDigits[ -LambertW[ -Log[E - 2]]/Log[E - 2], 10, 105][[1]]
Showing 1-4 of 4 results.

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

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