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.

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

Crossrefs

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

Crossrefs

Extensions

More terms from Jinyuan Wang, Mar 14 2020

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

Crossrefs

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

A138871 Last 3 digits of n-th even superperfect number A061652(n).

Original entry on oeis.org

2, 4, 16, 64, 96, 536, 144, 824, 976, 56, 64, 864, 576, 64, 544, 504, 176, 536, 496, 304, 56, 776, 96, 736, 376, 256, 336, 104, 504, 656, 224, 944, 296, 264, 856, 576, 136, 896, 536, 24, 704, 624, 936, 936, 464, 376, 256, 976
Offset: 1

Views

Author

Omar E. Pol, Apr 02 2008

Keywords

Comments

Also, last 3 digits of n-th superperfect number A019279(n), if there are no odd superperfect numbers.

Crossrefs

Formula

a(n) = 2^(A000043(n)-1) mod 1000. - Max Alekseyev, Feb 16 2024

Extensions

More terms from R. J. Mathar, Feb 05 2010
a(40)-a(41) from Max Alekseyev, Feb 11 2012
a(42)-a(47) from Jinyuan Wang, Mar 14 2020
a(48) from Max Alekseyev, Feb 16 2024
Showing 1-4 of 4 results.