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A139224 M(M-1)/2, where M is Mersenne prime A000668(n). +0
6
3, 21, 465, 8001, 33542145, 8589737985, 137438167041 (list; graph; listen)
OFFSET

1,1

COMMENT

Perfect number A000396(n) minus Mersenne prime A000668(n).

LINKS

O. E. Pol, Determinacion geometrica de los numeros primos y perfectos".

FORMULA

a(n)=A000668(n)*(A000668(n)-1)/2. Also a(n)=A000396(n)-A000668(n).

CROSSREFS

Cf. A000217, A000396, A000668, A036689, A139096, A139115, A139116, A139223, A139225, A139226, A139256, A139306.

Sequence in context: A108716 A084620 A120603 this_sequence A032469 A006927 A014375

Adjacent sequences: A139221 A139222 A139223 this_sequence A139225 A139226 A139227

KEYWORD

more,nonn

AUTHOR

Omar E. Pol (info(AT)polprimos.com), May 10 2008

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Last modified September 6 16:04 EDT 2008. Contains 143483 sequences.


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