A233416 c-perfect numbers.

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

Offset

1,1

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)

Links

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

Index entries for sequences related to binary expansion of n

Formula

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

Example

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.

Crossrefs

Cf. A124771, A233394.

Sequence in context: A333408 A174202 A139850 * A174822 A201790 A268985

Adjacent sequences: A233413 A233414 A233415 * A233417 A233418 A233419

Keyword

nonn,more,base

Author

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

Extensions

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

Status

approved