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 1-5 of 5 results.

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

A138862 First two (i.e., the two most significant) digits of n-th Mersenne prime A000668(n).

Original entry on oeis.org

3, 7, 31, 12, 81, 13, 52, 21, 23, 61, 16, 17, 68, 53, 10, 14, 44, 25, 19, 28, 47, 34, 28, 43, 44, 40, 85, 53, 52, 51, 74, 17, 12, 41, 81, 62, 12, 43, 92, 12, 29, 12, 31, 12, 20, 16, 31
Offset: 1

Views

Author

Omar E. Pol, Apr 02 2008

Keywords

Links

Crossrefs

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

Programs

  • Mathematica
    Join[{3,7},FromDigits[Take[IntegerDigits[#],2]]&/@ (2^MersennePrimeExponent[ Range[ 3,47]]-1)] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 01 2020 *)

Extensions

a(40)-a(47) from Ivan Panchenko, Aug 03 2018
Definition clarified by Harvey P. Dale, Aug 01 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

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
Showing 1-5 of 5 results.

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