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A139115 a(n) = p*(p - 1), where p is A000043(n). 5
2, 6, 20, 42, 156, 272, 342, 930, 3660, 7832, 11342, 16002, 270920, 367842, 1634562, 4851006, 5200680, 10345872, 18083756, 19558506, 93867032, 98813540, 125720156, 397464032, 470911700, 538634472, 1979938512, 7437768806, 12210802506 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
a(n) = A000043(n)*(A000043(n) - 1).
MATHEMATICA
#(#-1)&/@MersennePrimeExponent[Range[30]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jan 15 2020 *)
CROSSREFS
Sequence in context: A036689 A355390 A226326 * A193538 A121128 A056820
KEYWORD
nonn
AUTHOR
Omar E. Pol, May 10 2008
EXTENSIONS
More terms from Vincenzo Librandi, May 11 2010
STATUS
approved

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Last modified March 29 08:53 EDT 2024. Contains 371268 sequences. (Running on oeis4.)