A138823 Divisors of 248 (the 3rd perfect number divided by 2), written in base 2.

1, 10, 100, 1000, 11111, 111110, 1111100, 11111000

Offset

1,2

Comments

248 is the number of dimensions of E_8.

a(n) has n digits.

Links

Table of n, a(n) for n=1..8.

Index entries for sequences related to divisors of numbers

Example

The structure of divisors of 248 (see A018355)
..................................................................
n ............ Divisor . Formula ....... Divisor written in base 2
..................................................................
1) ................. 1 = 2^0 ........... 1
2) ................. 2 = 2^1 ........... 10
3) ................. 4 = 2^2 ........... 100
4) A134708(3) = .... 8 = 2^3 ........... 1000
5) A000668(3) = ... 31 = 2^5 - 2^0 ..... 11111
6) ................ 62 = 2^6 - 2^1 ..... 111110
7) ............... 124 = 2^7 - 2^2 ..... 1111100
8) A133028(3) = .. 248 = 2^8 - 2^3 ..... 11111000

Mathematica

FromDigits[IntegerDigits[#, 2]]&/@Divisors[248] (* Harvey P. Dale, Apr 01 2017 *)

Prog

(PARI) divisors(248) \\ Charles R Greathouse IV, Sep 06 2016

Crossrefs

Perfect number divided by 2: A133028. Cf. A000043, A000396, A000668, A018355, A090748, A134708, A135653.

Sequence in context: A290857 A290657 A286864 * A145442 A267456 A282580

Adjacent sequences: A138820 A138821 A138822 * A138824 A138825 A138826

Keyword

easy,fini,full,nonn,less

Author

Omar E. Pol, Mar 31 2008, corrected Apr 03 2008

Status

approved