OFFSET
1,1
COMMENTS
Numbers of the form 2*p^2 where p runs through the primes.
For these numbers m, there are precisely 5 groups of order m, hence this is a subsequence of A054397. If p = 2, these 5 groups of order 8 are described in example section of A054397, and when p is odd prime, the five corresponding groups are described in a comment of A143928. - Bernard Schott, Dec 11 2021
REFERENCES
Pascal Ortiz, Exercices d'Algèbre, Collection CAPES / Agrégation, Ellipses, problème 1.35, pp. 70-74, 2004.
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..1000
FORMULA
EXAMPLE
a(2) = prime(2)^2*2 = 3^2*2 = 9*2 = 18.
MATHEMATICA
2 Prime[Range[40]]^2 (* Vincenzo Librandi, Mar 27 2014 *)
PROG
(PARI) forprime (p=2, 100, print1(p^2*2", "))
(Haskell)
a079704 = (* 2) . a001248 -- Reinhard Zumkeller, Nov 19 2013
(Magma) [2*p^2: p in PrimesUpTo(200)]; // Vincenzo Librandi, Mar 27 2014
(Python)
from sympy import primerange
print([2*p**2 for p in primerange(1, 200)]) # Michael S. Branicky, Dec 11 2021
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jon Perry, Jan 31 2003
EXTENSIONS
More terms from Vincenzo Librandi, Jan 29 2010
Offset corrected by Reinhard Zumkeller, Nov 19 2013
STATUS
approved