A233416 c-perfect numbers.

11, 71, 226, 3676, 16911, 1143267, 4721203, 8906035

Offset: 1

Author

Vladimir Shevelev and Peter J. C. Moses, Dec 09 2013

Keywords

• nonn
• more
• base

Comments

A number k is called a c-perfect number if the sum of its proper c-divisors equals k.

For the definition of a c-divisor of an integer, see comment in A124771.

From Charlie Neder, Jan 17 2019: (Start)

Sequence in binary: 1011, 1000111, 11100010, 111001011100, 100001000001111, 100010111000111100011, 10010000000101000110011, 100001111110010100110011...

Next term > 10^7. (End)

Examples

			For n=11 which is a concatenation of binary parts (10)(1)(1); we have proper positive c-divisors 1, 2, 3, and 5, the sum of which is 11, so 11 is in the sequence.
		

Links

• Index entries for sequences related to binary expansion of n

Crossrefs

Cf. A124771, A233394.

Formula

A233394(a(n))=2*a(n).

Extensions

a(6)-a(8) from Charlie Neder, Jan 17 2019