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.

Previous Showing 11-15 of 15 results.

A144541 Unique sequence of digits a(0), a(1), a(2), .. such that for all k >= 2, the number A(k) := Sum_{n = 0..k-1 } a(n)*10^n satisfies 13^A(k) == A(k) mod 10^k.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Dec 20 2008

Keywords

Examples

			350540552884591812248887692071686904673235689443665663593170433746147669728547...
		

References

  • M. Ripà, La strana coda della serie n^n^...^n, Trento, UNI Service, Nov 2011, p. 69-78. ISBN 978-88-6178-789-6.
  • Ilan Vardi, "Computational Recreations in Mathematica," Addison-Wesley Publishing Co., Redwood City, CA, 1991, pages 226-229.

Crossrefs

Programs

  • Mathematica
    (* Import Mmca coding for "SuperPowerMod" and "LogStar" from text file in A133612 and then *) $RecursionLimit = 2^14; f[n_] := SuperPowerMod[13, n + 1, 10^n]; Reverse@ IntegerDigits@ f@ 105 (* Robert G. Wilson v, Mar 06 2014 *)

Extensions

a(68) onward from Robert G. Wilson v, Mar 06 2014

A144542 Unique sequence of digits a(0), a(1), a(2), .. such that for all k >= 2, the number A(k) := Sum_{n = 0..k-1 } a(n)*10^n satisfies 14^A(k) == A(k) mod 10^k.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Dec 20 2008

Keywords

Examples

			633205765773282307762880481730639884053299234674143456126141831703991362480509...
		

References

  • M. Ripà, La strana coda della serie n^n^...^n, Trento, UNI Service, Nov 2011, p. 69-78. ISBN 978-88-6178-789-6.
  • Ilan Vardi, "Computational Recreations in Mathematica," Addison-Wesley Publishing Co., Redwood City, CA, 1991, pages 226-229.

Crossrefs

Programs

  • Mathematica
    (* Import Mmca coding for "SuperPowerMod" and "LogStar" from text file in A133612 and then *) $RecursionLimit = 2^14; f[n_] := SuperPowerMod[14, n + 1, 10^n]; Reverse@ IntegerDigits@ f@ 105 (* Robert G. Wilson v, Mar 06 2014 *)

Extensions

a(68) onward from Robert G. Wilson v, Mar 06 2014

A144543 Unique sequence of digits a(0), a(1), a(2), .. such that for all k >= 2, the number A(k) := Sum_{n = 0..k-1 } a(n)*10^n satisfies 15^A(k) == A(k) mod 10^k.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Dec 20 2008

Keywords

Examples

			573958083567096086449346119283793862477858654472393049431441904930012219852452...
		

References

  • M. Ripà, La strana coda della serie n^n^...^n, Trento, UNI Service, Nov 2011, p. 69-78. ISBN 978-88-6178-789-6.
  • Ilan Vardi, "Computational Recreations in Mathematica," Addison-Wesley Publishing Co., Redwood City, CA, 1991, pages 226-229.

Crossrefs

Programs

  • Mathematica
    (* Import Mmca coding for "SuperPowerMod" and "LogStar" from text file in A133612 and then *) $RecursionLimit = 2^14; f[n_] := SuperPowerMod[15, n + 1, 10^n]; Reverse@ IntegerDigits@ f@ 105 (* Robert G. Wilson v, Mar 06 2014 *)

Extensions

a(68) onward from Robert G. Wilson v, Mar 06 2014

A206636 a(n) = 2^^(n+2) modulo 10^n, where ^^ denotes a power tower (see A133612).

Original entry on oeis.org

6, 36, 736, 8736, 48736, 948736, 2948736, 32948736, 432948736, 3432948736, 53432948736, 353432948736, 5353432948736, 75353432948736, 75353432948736, 5075353432948736, 15075353432948736, 615075353432948736, 8615075353432948736, 98615075353432948736, 98615075353432948736, 8098615075353432948736
Offset: 1

Views

Author

Marco Ripà, Feb 10 2012

Keywords

Comments

Backward concatenation of A133612.
For all m>n+1, 2^^m == 2^^(n+2) (mod 10^n). Hence, each term represents the trailing decimal digits of 2^^m for every sufficiently large m.

References

  • M. Ripà, La strana coda della serie n^n^...^n, Trento, UNI Service, Nov 2011. ISBN 978-88-6178-789-6.

Crossrefs

Programs

  • Mathematica
    (* first load all lines of Super Power Mod by Ilan Vardi from the hyper-link, then *) $RecursionLimit = 2^14;  a[n_] := SuperPowerMod[2, n +2, 10^n]; Array[a, 22] (* Robert G. Wilson v, Apr 20 2020 *)

Formula

a(n) = A014221(n+3) mod (10^n).
For n>1, a(n) = 2^a(n-1) mod 10^n.

A318478 Decimal digits such that for all k>=1, the number A(k) := Sum_{n = 0..k-1 } a(n)*10^n satisfies the congruence 1984^A(k) == A(k) (mod 10^k).

Original entry on oeis.org

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

Views

Author

Marco Ripà, Aug 26 2018

Keywords

Comments

10-adic expansion of the iterated exponential 1984^^n for sufficiently large n (where c^^n denotes a tower of c's of height n). E.g., for n>=9, 1984^^n(mod 10^8) == 98703616.
1984^^n, for any n>=188, appears in M. Ripà's book "La strana coda della serie n^n^...^n", where the author took his birth year (1984), as a random base in order to prove some general properties about tetration, and calculating 1984^^n(mod 10^187) as a test for his paper-and-pencil procedure.

Examples

			1984^^1984 (mod 10^8) == 98703616.
Thus, 1984^^1984 = ...61630789307145912032948400109045102(...)7490335.
Consider the sequence 1984^^n: 1984, 1984^1984, 1984^(1984^1984), ... From 1984^^3 onwards, all terms end with the digits 16. This follows from Euler's generalization of Fermat's little theorem.
		

References

  • M. Gardner, Mathematical Games, Scientific American 237, 18 - 28 (1977).
  • M. Ripà, La strana coda della serie n^n^...^n, Trento, UNI Service, Nov 2011, p. 78-79. ISBN 978-88-6178-789-6.
  • Ilan Vardi, "Computational Recreations in Mathematica," Addison-Wesley Publishing Co., Redwood City, CA, 1991, pages 226-229.

Crossrefs

Previous Showing 11-15 of 15 results.