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 1-10 of 11 results. Next

A139294 a(n) = 2^(2p - 1), where p is the n-th Mersenne prime A000668(n).

Original entry on oeis.org

32, 8192, 2305843009213693952, 14474011154664524427946373126085988481658748083205070504932198000989141204992
Offset: 1

Views

Author

Omar E. Pol, Apr 13 2008

Keywords

Comments

Next terms have 4932, 78913, 315652, 1292913986, and 1388255822130839283 decimal digits. - Jens Kruse Andersen, Jul 14 2014

Crossrefs

Programs

  • Mathematica
    A000668 := Select[2^Range[500] - 1, PrimeQ]; Table[2^(2*A000668[[n]] - 1), {n, 1, 5}] (* G. C. Greubel, Oct 03 2017 *)
    a[n_] := 2^(2^(MersennePrimeExponent[n] + 1) - 3); Array[a, 4] (* Amiram Eldar, Jul 10 2025 *)
  • PARI
    \p 100
    print1("a(n): "); forprime(q=2, 7, p=2^q-1; if(isprime(p), print1(2^(2*p-1)", ")));
    print1("\nNumber of digits in a(n): "); forprime(q=2, 127, p=2^q-1; if(isprime(p), print1(ceil((2*p-1)*log(2)/log(10))", "))) \\ Jens Kruse Andersen, Jul 14 2014

Formula

a(n) = 2^(2*A000668(n)-1).

A139295 a(n) = 2^(2p - 1)-1, where p is the n-th Mersenne prime A000668(n).

Original entry on oeis.org

31, 8191, 2305843009213693951, 14474011154664524427946373126085988481658748083205070504932198000989141204991
Offset: 1

Views

Author

Omar E. Pol, Apr 13 2008

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := 2^(2^(MersennePrimeExponent[n] + 1) - 3) - 1; Array[a, 4] (* Amiram Eldar, Jul 10 2025 *)

Formula

a(n) = 2^(2*A000668(n)-1)-1 = A139294(n)-1.

A139296 a(n) = 2^(2p - 1)/2, where p is the n-th Mersenne prime A000668(n).

Original entry on oeis.org

16, 4096, 1152921504606846976, 7237005577332262213973186563042994240829374041602535252466099000494570602496
Offset: 1

Views

Author

Omar E. Pol, Apr 13 2008

Keywords

Comments

a(5) has 4931 digits and is too large to include. - R. J. Mathar, May 30 2008

Crossrefs

Programs

  • Mathematica
    a[n_] := 2^(2^(MersennePrimeExponent[n] + 1) - 4); Array[a, 4] (* Amiram Eldar, Jul 10 2025 *)

Formula

a(n) = 2^(2*A000668(n)-1)/2.

Extensions

One more term from R. J. Mathar, May 30 2008

A139297 a(n) = 2^(2p - 1)/2-1, where p is the n-th Mersenne prime A000668(n).

Original entry on oeis.org

15, 4095, 1152921504606846975, 7237005577332262213973186563042994240829374041602535252466099000494570602495
Offset: 1

Views

Author

Omar E. Pol, Apr 13 2008

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := 2^(2^(MersennePrimeExponent[n] + 1) - 4) - 1; Array[a, 4] (* Amiram Eldar, Jul 10 2025 *)

Formula

a(n) = 2^(2*A000668(n)-1)/2-1 = A139296(n)-1.

Extensions

a(4) from Amiram Eldar, Jul 10 2025

A139299 a(n) = 2^(2p - 1)/4-1, where p is the n-th Mersenne prime A000668(n).

Original entry on oeis.org

7, 2047, 576460752303423487, 3618502788666131106986593281521497120414687020801267626233049500247285301247
Offset: 1

Views

Author

Omar E. Pol, Apr 13 2008

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := 2^(2^(MersennePrimeExponent[n] + 1) - 5) - 1; Array[a, 4] (* Amiram Eldar, Jul 10 2025 *)

Formula

a(n) = 2^(2*A000668(n)-1)/4-1 = A139294(n)/4-1 = A139298(n)-1.

Extensions

a(4) from Amiram Eldar, Jul 10 2025

A139300 a(n) = 2^(2p - 1)/8, where p is the n-th Mersenne prime A000668(n).

Original entry on oeis.org

4, 1024, 288230376151711744, 1809251394333065553493296640760748560207343510400633813116524750123642650624
Offset: 1

Views

Author

Omar E. Pol, Apr 13 2008

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := 2^(2^(MersennePrimeExponent[n] + 1) - 6); Array[a, 4] (* Amiram Eldar, Jul 10 2025 *)

Formula

a(n) = 2^(2*A000668(n)-1)/8 = A139294(n)/8.

Extensions

a(4) from Amiram Eldar, Jul 10 2025

A139301 a(n) = (2^(2p - 1)/8)-1, where p is the n-th Mersenne prime A000668(n).

Original entry on oeis.org

3, 1023, 288230376151711743, 1809251394333065553493296640760748560207343510400633813116524750123642650623
Offset: 1

Views

Author

Omar E. Pol, Apr 13 2008

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := 2^(2^(MersennePrimeExponent[n] + 1) - 6) - 1; Array[a, 4] (* Amiram Eldar, Jul 10 2025 *)

Formula

a(n) = (2^(2*A000668(n)-1)/8)-1 = (A139294(n)/8)-1.

Extensions

a(4) from Amiram Eldar, Jul 10 2025

A139302 a(n) = 2^(2p - 1)/16, where p is the n-th Mersenne prime A000668(n).

Original entry on oeis.org

2, 512, 144115188075855872, 904625697166532776746648320380374280103671755200316906558262375061821325312
Offset: 1

Views

Author

Omar E. Pol, Apr 13 2008

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := 2^(2^(MersennePrimeExponent[n] + 1) - 7); Array[a, 4] (* Amiram Eldar, Jul 10 2025 *)

Formula

a(n) = 2^(2*A000668(n)-1)/16 = A139294(n)/16.

Extensions

a(4) from Amiram Eldar, Jul 10 2025

A139303 a(n) = (2^(2p - 1)/16)-1, where p is the n-th Mersenne prime A000668(n).

Original entry on oeis.org

1, 511, 144115188075855871, 904625697166532776746648320380374280103671755200316906558262375061821325311
Offset: 1

Views

Author

Omar E. Pol, Apr 13 2008

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := 2^(2^(MersennePrimeExponent[n] + 1) - 7) - 1; Array[a, 4] (* Amiram Eldar, Jul 10 2025 *)

Formula

a(n) = (2^(2*A000668(n)-1)/16)-1 = (A139294(n)/16)-1.

Extensions

a(4) from Amiram Eldar, Jul 10 2025

A139304 a(n) = 2^(2p - 1)/32, where p is the n-th Mersenne prime A000668(n).

Original entry on oeis.org

1, 256, 72057594037927936, 452312848583266388373324160190187140051835877600158453279131187530910662656
Offset: 1

Views

Author

Omar E. Pol, Apr 13 2008

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := 2^(2^(MersennePrimeExponent[n] + 1) - 8); Array[a, 4] (* Amiram Eldar, Jul 10 2025 *)

Formula

a(n) = 2^(2*A000668(n)-1)/32 = A139294(n)/32.

Extensions

a(4) from Amiram Eldar, Jul 10 2025
Showing 1-10 of 11 results. Next