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 1-2 of 2 results.

A152961 Base-2 logarithm of A136007(n)+1.

Original entry on oeis.org

2, 3, 5, 7, 13, 17, 19, 31, 61, 127, 521, 2281, 3217, 4253, 9941, 19937, 21701, 23209, 44497, 110503, 216091, 859433, 1257787, 3021377, 6972593, 13466917, 20996011, 30402457, 32582657, 42643801, 57885161
Offset: 1

Views

Author

Omar E. Pol, Dec 16 2008, Dec 20 2008

Keywords

Comments

The first 10 terms coincide with A109799.

Crossrefs

Intersection of A000043 and A136002.
Cf. A000523, A109799, A136003, A136005, A136007.

Programs

  • Mathematica
    q[n_] := n == 2 || Module[{d = Divisors[(n+1)/2]}, AllTrue[Range[3, Length[d]], d[[#]] >= 2 * d[[#-1]] &]]; Select[MersennePrimeExponent[Range[48]], q] (* Amiram Eldar, Oct 20 2024 *)

Formula

a(n) = A000523(A136007(n)+1). - Michel Marcus, Apr 14 2021

Extensions

a(12)-(a31) from Amiram Eldar, Oct 20 2024

A152953 a(n) = A136007(n)*(A136007(n)+1)/2.

Original entry on oeis.org

6, 28, 496, 8128, 33550336, 8589869056, 137438691328, 2305843008139952128, 2658455991569831744654692615953842176, 14474011154664524427946373126085988481573677491474835889066354349131199152128
Offset: 1

Views

Author

Omar E. Pol, Dec 15 2008

Keywords

Comments

Different from A000396.

Crossrefs

Cf. A000396, A136007.
Showing 1-2 of 2 results.

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