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.

A138869 Concatenation of first two digits and last two digits of n-th even superperfect number A061652(n).

Original entry on oeis.org

22, 44, 1616, 6464, 4096, 6536, 2644, 1024, 1176, 3056, 8164, 8564, 3476, 2664, 5244, 7304, 2276, 1236, 9596, 1404, 2356, 1776, 1496, 2136, 2276, 2056, 4236, 2604, 2604, 2556, 3724, 8744, 6496, 2064, 4056, 3176, 6336, 2196, 4636, 6224, 1404, 6124, 1536, 6236, 1064, 8476, 1556
Offset: 1

Views

Author

Omar E. Pol, Apr 02 2008

Keywords

Comments

Also, concatenation of first two digits and last two digits of n-th superperfect number A019279(n), if there are no odd superperfect numbers.

Crossrefs

Cf. A019279, A061652, A138863, A138867, A138868, A138875.

Extensions

More terms from Jinyuan Wang, Mar 14 2020

A138873 First two digits of n-th even perfect number.

Original entry on oeis.org

6, 28, 49, 81, 33, 85, 13, 23, 26, 19, 13, 14, 23, 14, 54, 10, 99, 33, 18, 40, 11, 59, 39, 93, 10, 81, 36, 14, 13, 13, 27, 15, 83, 84, 33, 19, 81, 95, 42, 79, 44, 74, 49, 77, 20, 14, 50
Offset: 1

Views

Author

Omar E. Pol, Apr 02 2008

Keywords

Links

Crossrefs

Cf. A000396, A138862, A138875.
First 2 digits of sequence A138875. [Steven Bi (chenhsi(AT)stanford.edu), Jan 18 2009]

Programs

  • Mathematica
    Join[{6},FromDigits[Take[IntegerDigits[#],2]]&/@PerfectNumber[Range[2,50]]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Sep 26 2020 *)

Extensions

a(15)-a(31) added by Steven Bi (chenhsi(AT)stanford.edu), Jan 18 2009
Definition changed (inserting the word "even") and a(37)-a(47) added by Ivan Panchenko, Aug 04 2018

A138874 Last two digits of the n-th even perfect number.

Original entry on oeis.org

6, 28, 96, 28, 36, 56, 28, 28, 76, 16, 28, 28, 76, 28, 28, 28, 76, 56, 36, 28, 16, 76, 36, 56, 76, 16, 56, 28, 28, 16, 28, 28, 36, 28, 16, 76, 56, 36, 56, 28, 28, 28, 56, 56, 28, 76, 16
Offset: 1

Views

Author

Omar E. Pol, Apr 02 2008

Keywords

Links

  • Édouard Lucas: Théorie des nombres. Vol. 1: Le calcul des nombres entiers. Le calcul des nombres rationnels. La divisibilité arithmétique. Paris: Gauthier-Villars, 1891, Nr. 229 (Théorème de Fermat), Ex. V, p. 424-425.
  • Omar E. Pol, Los numeros perfectos

Crossrefs

Cf. A000396, A080173, A104511, A138875.

Extensions

Definition changed (inserting the word "even") and a(39)-a(47) added by Ivan Panchenko, Aug 04 2018
Showing 1-3 of 3 results.

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