|
Search: id:A064549
|
|
|
| A064549 |
|
a(n) = n * Product_{primes p|n} p. |
|
+0
6
|
|
| 1, 4, 9, 8, 25, 36, 49, 16, 27, 100, 121, 72, 169, 196, 225, 32, 289, 108, 361, 200, 441, 484, 529, 144, 125, 676, 81, 392, 841, 900, 961, 64, 1089, 1156, 1225, 216, 1369, 1444, 1521, 400, 1681, 1764, 1849, 968, 675, 2116, 2209, 288, 343, 500, 2601, 1352
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
LINKS
|
Harry J. Smith, Table of n, a(n) for n=1,...,1000
|
|
FORMULA
|
Multiplicative with a(p^k)=p^(k+1) when k>0.
a(n) = n*A007947(n) = n^2/A003557(n).
|
|
EXAMPLE
|
a(12)=72 since 12=2^2*3 and 12*2*3 = 72.
|
|
PROGRAM
|
(PARI) popf(n)= { local(f, p=1); f=factor(n); for(i=1, matsize(f)[1], p*=f[i, 1]); return(p) } { for (n=1, 1000, write("b064549.txt", n, " ", n*popf(n)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Sep 18 2009]
|
|
CROSSREFS
|
A permutation of the powerful numbers A001694.
Sequence in context: A050399 A072995 A073395 this_sequence A087687 A164382 A145521
Adjacent sequences: A064546 A064547 A064548 this_sequence A064550 A064551 A064552
|
|
KEYWORD
|
mult,nonn
|
|
AUTHOR
|
Henry Bottomley (se16(AT)btinternet.com), Oct 16 2001
|
|
|
Search completed in 0.002 seconds
|
