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

Author

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

Keywords

• easy
• fini
• full
• nonn
• less

Comments

248 is the number of dimensions of E_8.

a(n) has n digits.

Examples

			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
		

Links

• Index entries for sequences related to divisors of numbers

Crossrefs

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

Programs

Mathematica

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

PARI

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