|
Search: id:A111360
|
|
|
| A111360 |
|
Positive integers n such that the sum of the divisors of n and the n-th prime is divisible by n. |
|
+0
1
|
|
| 1, 2, 3, 9, 21, 129, 5663, 40087, 184971, 246901, 251737, 1610143, 3098384123, 19819945093, 21323898091
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
COMMENT
|
No further term between 1610143 and 73*10^6. - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Feb 11 2008
|
|
EXAMPLE
|
The divisors of 21 are 1,3,7,21 and the 21st prime is 73. 1+3+7+21+73 = 105, which is divisible by 21.
|
|
MATHEMATICA
|
Select[Range[10^8], Mod[Prime[ # ] + Plus @@ Divisors[ # ], # ] == 0 &] (*Chandler*)
|
|
PROGRAM
|
(PARI) { p=2; for(n=1, 100000000, if( (sigma(n)+p) % n == 0, print(n) ) ; p=nextprime(p+1) ; ) ; } - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Feb 11 2008
|
|
CROSSREFS
|
Sequence in context: A077550 A056780 A141505 this_sequence A111238 A057832 A089421
Adjacent sequences: A111357 A111358 A111359 this_sequence A111361 A111362 A111363
|
|
KEYWORD
|
more,nonn
|
|
AUTHOR
|
Ray G. Opao (1260(AT)email.com), Nov 07 2005
|
|
EXTENSIONS
|
a(13)-a(15) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Apr 22 2008
|
|
|
Search completed in 0.002 seconds
|
