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.

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A133024 Divisors of 8128, the 4th perfect number.

Original entry on oeis.org

1, 2, 4, 8, 16, 32, 64, 127, 254, 508, 1016, 2032, 4064, 8128
Offset: 1

Views

Author

Omar E. Pol, Oct 26 2007, Mar 03 2008, Dec 27 2008

Keywords

Comments

127 is the 4th Mersenne prime: A000668.
The number of divisors of the 4th perfect number is 2*A000043(4)=A061645(4)=14.
For the structure of this sequence and its binary expansion, see A135654.

Links

Crossrefs

Cf. A018254, A018487. Perfect numbers: A000396.
Cf. A000079, A000668, A061645, A133033, A135654.

Programs

Formula

For n=1..7 : a(n) = 2^(n-1). For n=8..14: a(n) = 2^(n-1) - 2^(n-8) = A000668(4)*2^(n-8).

A133025 Divisors of 33550336, the 5th perfect number.

Original entry on oeis.org

1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8191, 16382, 32764, 65528, 131056, 262112, 524224, 1048448, 2096896, 4193792, 8387584, 16775168, 33550336
Offset: 1

Views

Author

Omar E. Pol, Oct 26 2007, Mar 03 2008, Dec 27 2008

Keywords

Comments

8191 is the 5th Mersenne prime: A000668.
The number of divisors of the 5th perfect number is 2*A000043(5)=A061645(5)=26.
For the structure of this sequence and its binary expansion, see A135655.

Links

Crossrefs

Cf. A018254, A018487. Perfect numbers: A000396.
Cf. A000043, A000079, A000668, A061645, A133033, A135655.

Programs

Formula

For n=1..13 : a(n) = 2^(n-1). For n=14..26: a(n) = 2^(n-1) - 2^(n-14) = A000668(5)*2^(n-14).
Previous Showing 11-12 of 12 results.

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