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A135651 Even superperfect numbers written in base 2. 1
10, 100, 10000, 1000000, 1000000000000, 10000000000000000, 1000000000000000000, 1000000000000000000000000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Also, superperfect numbers (A019279) written in base 2 (If there are no odd perfect numbers).

Also, concatenation of "1" and A090748(n) digits "0".

The number of digits of a(n) is equal to A000043(n) and also equal to the number of digits of n-th Mersenne prime written in base 2 (see A117293, A135650).

LINKS

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

EXAMPLE

a(3)=10000 because the 3rd even superperfect number A061652(3)=16 and 16 written in base 2 is equal to 10000.

CROSSREFS

Cf. A000043, A000668, A019279, A061652, A090748, A117293, A135650.

Sequence in context: A249457 A173482 A173481 * A220812 A139103 A067217

Adjacent sequences:  A135648 A135649 A135650 * A135652 A135653 A135654

KEYWORD

base,nonn

AUTHOR

Omar E. Pol, Feb 23 2008

STATUS

approved

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Last modified December 2 17:59 EST 2021. Contains 349445 sequences. (Running on oeis4.)