|
| |
|
|
A139226
|
|
M(M-1)/6, where M is Mersenne prime A000668(n).
|
|
5
| |
|
|
1, 7, 155, 2667, 11180715, 2863245995, 45812722347, 768614335330822827, 886151997189943914116283202246716075, 63853980869412035764931125821777872829435728032869035, 4388012152856549445746584486819520216982214368341183846591146667, 4824670384888174809315457708695329493801178769338122219111555681805105015467
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| Perfect number A000396(n) minus Mersenne prime A000668(n), divided by 3.
Terms from a(13) on have 313 or more digits and are not listed for that reason. - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 11 2008
|
|
|
LINKS
| O. E. Pol, Determinacion geometrica de los numeros primos y perfectos".
|
|
|
FORMULA
| a(n)=A000668(n)*(A000668(n)-1)/6 = A139223(n)/6 = A139224(n)/3. Also a(n)=(A000396(n)-A000668(n))/3.
|
|
|
CROSSREFS
| Cf. A000217, A000396, A000668, A036689, A139096, A139115, A139116, A139223, A139224, A139225, A139256, A139306.
Sequence in context: A144683 A141835 A111831 * A197595 A197979 A203584
Adjacent sequences: A139223 A139224 A139225 * A139227 A139228 A139229
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Omar E. Pol (info(AT)polprimos.com), May 10 2008
|
|
|
EXTENSIONS
| More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 11 2008
|
| |
|
|
