login
Divisors of 20: a finite sequence associated with the Lie algebra A_4.
1

%I #19 Jan 27 2018 18:19:42

%S 1,2,4,5,10,20

%N Divisors of 20: a finite sequence associated with the Lie algebra A_4.

%D E. B. Dynkin, Semisimple subalgebras of semisimple Lie algebras, Am. Math. Soc. Translations, Series 2, Vol. 6, 1957, pp. 111-244, esp. p. 211.

%H <a href="/index/Di#divisors">Index entries for sequences related to divisors of numbers</a>

%F a(n) = A161706(n-1). - _Reinhard Zumkeller_, Jun 21 2009

%o (Sage) divisors(20); # _Zerinvary Lajos_, Jun 13 2009

%o (PARI) divisors(20)

%K nonn,fini,full,easy

%O 1,2

%A _N. J. A. Sloane_