|
Search: id:A135323
|
|
|
| A135323 |
|
a(1)=1. a(n) = sum{p=prime, p|n} a(n/p)*p. |
|
+0
1
|
|
| 1, 2, 3, 4, 5, 12, 7, 8, 9, 20, 11, 36, 13, 28, 30, 16, 17, 54, 19, 60, 42, 44, 23, 96, 25, 52, 27, 84, 29, 180, 31, 32, 66, 68, 70, 216, 37, 76, 78, 160, 41, 252, 43, 132, 135, 92, 47, 240, 49, 150, 102, 156, 53, 216, 110, 224, 114, 116, 59, 720, 61, 124, 189, 64, 130, 396
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
COMMENT
|
If p^k is a power of a prime, then a(p^k) = p^k.
|
|
LINKS
|
Leroy Quet, Home Page (listed in lieu of email address)
|
|
EXAMPLE
|
The primes that divide 12 are 2 and 3. So a(12) = a(12/2)*2 + a(12/3)*3 = 12*2 + 4*3 = 36.
|
|
MATHEMATICA
|
a = {1}; For[n = 2, n < 100, n++, b = Select[Divisors[n], PrimeQ[ # ] &]; AppendTo[a, Sum[a[[n/b[[j]]]]*b[[j]], {j, 1, Length[b]}]]]; a - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 07 2007
|
|
CROSSREFS
|
Adjacent sequences: A135320 A135321 A135322 this_sequence A135324 A135325 A135326
Sequence in context: A136367 A014545 A065636 this_sequence A052106 A064446 A143482
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Leroy Quet Dec 06 2007
|
|
EXTENSIONS
|
More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 07 2007
|
|
|
Search completed in 0.002 seconds
|
