OFFSET
1,1
COMMENTS
a(n) is the order of the matrix group PSL(2,prime(n)). - corrected by Tom Edgar, Sep 28 2015
REFERENCES
Blyth and Robertson, Essential Student Algebra, Volume 5: Groups,Chapman and Hall, New York, page 14
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..1000
FORMULA
a(n) = A127918(n), n>1.
MATHEMATICA
a[n_]= If[n==1, 6, Prime[n]*(Prime[n]^2 -1)/2];
Table[a[n], {n, 40}]
Join[{6}, Table[Prime[n] (Prime[n]^2 - 1)/2, {n, 2, 40}]] (* Vincenzo Librandi, Sep 29 2015 *)
PROG
(PARI) a(n) = prime(n)*(prime(n)^2-1)/2;
vector(40, n, a(n+1)) \\ Altug Alkan, Sep 28 2015
(Magma) [6] cat [NthPrime(n)*(NthPrime(n)^2-1)/2: n in [2..40]]; // Vincenzo Librandi, Sep 29 2015
(SageMath)
def A117762(n): return nth_prime(n)*(nth_prime(n)^2-1)/2 + 3*int(n==1)
[A117762(n) for n in range(1, 41)] # G. C. Greubel, Jul 21 2023
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Roger L. Bagula, Apr 14 2006
STATUS
approved