|
| |
|
|
A138113
|
|
Smallest number with same number of divisors as n*a(n-1).
|
|
3
| |
|
|
1, 2, 6, 24, 120, 720, 5040, 27720, 166320, 1441440, 7207200, 73513440, 367567200, 4655851200, 64250746560, 1028011944960, 5140059724800, 32607253879200, 260858031033600, 4620913692595200, 97039187544499200, 897612484786617600
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
FORMULA
| a(n) = A140635(n*a(n-1)) - J. Lowell (jhbubby(AT)mindspring.com), May 20 2008
|
|
|
EXAMPLE
| 5040*8=40320 has 96 divisors, but smallest number with 96 divisors is 27720
|
|
|
PROG
| (PARI) A138113(n)={ local(an1, t) ; if(n<=2, return(n) ) ; an1 = A138113(n-1) ; t=length(divisors(n*an1)) ; return(A005179(t)) ; } {for (n=1, 40, print1(A138113(n)", ") ; ) } [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Mar 20 2010]
|
|
|
CROSSREFS
| Cf. A019505 (2*a(n-1)).
Cf. A140635.
Sequence in context: A090583 A108889 A033645 * A045977 A177278 A173847
Adjacent sequences: A138110 A138111 A138112 * A138114 A138115 A138116
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| J. Lowell (jhbubby(AT)mindspring.com), May 04 2008
|
|
|
EXTENSIONS
| More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Mar 20 2010
|
| |
|
|
