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 1-7 of 7 results.

A138866 Concatenation of first 3 digits and last 3 digits of n-th Mersenne prime A000668(n).

Original entry on oeis.org

33, 77, 3131, 127127, 819191, 131071, 524287, 214647, 230951, 618111, 162127, 170727, 686151, 531127, 104087, 147007, 446351, 259071, 190991, 285607, 478111, 346551, 281191, 431471, 448751, 402511, 854671, 536207, 521007, 512311, 746447, 174887, 129591, 412527, 814711, 623151, 127271, 437791, 924071, 125047, 299407, 122247, 315871, 124871, 202927, 169751, 316511
Offset: 1

Views

Author

Omar E. Pol, Apr 02 2008

Keywords

Links

Crossrefs

Cf. A000668, A080173, A104511, A138816, A138817, A138840, A138841.

Programs

  • Mathematica
    Join[{33,77,3131},FromDigits[Flatten[Join[{Take[IntegerDigits[#],3],Take[ IntegerDigits[ #],-3]}]]]&/@ (2^MersennePrimeExponent[Range[4,40]]-1)] (* Harvey P. Dale, Dec 30 2023 *)

Extensions

More terms from Harvey P. Dale, Dec 30 2023

A138864 First 3 digits of n-th Mersenne prime A000668(n).

Original entry on oeis.org

3, 7, 31, 127, 819, 131, 524, 214, 230, 618, 162, 170, 686, 531, 104, 147, 446, 259, 190, 285, 478, 346, 281, 431, 448, 402, 854, 536, 521, 512, 746, 174, 129, 412, 814, 623, 127, 437, 924, 125, 299, 122, 315, 124, 202, 169, 316
Offset: 1

Views

Author

Omar E. Pol, Apr 02 2008

Keywords

Links

Crossrefs

Cf. A000668, A080173, A104511, A138863, A138864, A138865, A138866.

Extensions

a(40)-a(47) from Ivan Panchenko, Aug 03 2018

A138863 Concatenation of first two digits and last two digits of n-th Mersenne prime A000668(n).

Original entry on oeis.org

33, 77, 3131, 1227, 8191, 1371, 5287, 2147, 2351, 6111, 1627, 1727, 6851, 5327, 1087, 1407, 4451, 2571, 1991, 2807, 4711, 3451, 2891, 4371, 4451, 4011, 8571, 5307, 5207, 5111, 7447, 1787, 1291, 4127, 8111, 6251, 1271, 4391, 9271, 1247, 2907, 1247, 3171, 1271, 2027, 1651, 3111
Offset: 1

Views

Author

Omar E. Pol, Apr 02 2008

Keywords

Links

Crossrefs

Cf. A000668, A080173, A104511, A138816, A138817, A138840, A138841, A138862, A138864, A138865, A138866.

Extensions

More terms from Jinyuan Wang, Mar 14 2020

A138865 Last 3 digits of n-th Mersenne prime A000668(n).

Original entry on oeis.org

3, 7, 31, 127, 191, 71, 287, 647, 951, 111, 127, 727, 151, 127, 87, 7, 351, 71, 991, 607, 111, 551, 191, 471, 751, 511, 671, 207, 7, 311, 447, 887, 591, 527, 711, 151, 271, 791, 71, 47, 407, 247, 871, 871, 927, 751, 511
Offset: 1

Views

Author

Omar E. Pol, Apr 02 2008

Keywords

Links

Crossrefs

Cf. A000668, A080173, A104511, A138862, A138863, A138864, A138866.

Programs

  • Mathematica
    Array[Mod[2^MersennePrimeExponent[#] - 1, 1000] &, 45] (* Michael De Vlieger, Aug 05 2018 *)

Extensions

a(40)-a(47) from Ivan Panchenko, Apr 03 2018

A138875 Concatenation of first two digits and last two digits of n-th even perfect number.

Original entry on oeis.org

66, 2828, 4996, 8128, 3336, 8556, 1328, 2328, 2676, 1916, 1328, 1428, 2376, 1428, 5428, 1028, 9976, 3356, 1836, 4028, 1116, 5976, 3936, 9356, 1076, 8116, 3656, 1428, 1328, 1316, 2728, 1528, 8336, 8428, 3316, 1976, 8156, 9536, 4256, 7928, 4428, 7428, 4956, 7756, 2028, 1476, 5016
Offset: 1

Views

Author

Omar E. Pol, Apr 02 2008

Keywords

Links

Crossrefs

Cf. A000396, A104511, A138843, A138863, A138866, A138877.

Extensions

More terms from http://amicable.homepage.dk/perfect.htm sent by Steven Bi (chenhsi(AT)stanford.edu), Dec 22 2008
More terms from same site sent by Steven Bi (chenhsi(AT)stanford.edu), Jan 09 2009
More terms from Jinyuan Wang, Mar 14 2020

A138877 Concatenation of first 3 digits and last 3 digits of n-th perfect number.

Original entry on oeis.org

66, 2828, 496496, 812128, 335336, 858056, 137328, 230128, 265176, 191216, 131128, 144128, 235976, 141128, 541328, 108528, 994776, 335056, 182536, 407528, 114216, 598576, 395336, 931656, 100376, 811816, 365456, 144528, 136528, 131016, 278128
Offset: 1

Views

Author

Omar E. Pol, Apr 02 2008

Keywords

Links

Crossrefs

Cf. A000396, A104511, A138843, A138866.

Extensions

Added terms 15-33 and corrected 1 term Steven Bi (chenhsi(AT)stanford.edu), Jan 13 2009

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 1-7 of 7 results.

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