|
Search: id:A076981
|
|
|
| A076981 |
|
Smallest k such that n*(n+1)*(n+2)*...*(n+k) is divisible by the product of primes up to n. |
|
+0
1
|
|
| 0, 0, 1, 2, 1, 4, 3, 6, 5, 4, 4, 10, 9, 12, 11, 10, 9, 16, 15, 18, 17, 16, 15, 22, 21, 20, 19, 18, 17, 28, 27, 30, 29, 28, 27, 26, 25, 36, 35, 34, 33, 40, 39, 42, 41, 40, 39, 46, 45, 44, 43, 42, 41, 52, 51, 50, 49, 48, 47, 58, 57, 60, 59, 58, 57, 56, 55, 66, 65, 64, 63, 70, 69
(list; graph; listen)
|
|
|
OFFSET
|
0,4
|
|
|
FORMULA
|
For any n, a(n)<n. If p is prime, a(p+1)=p-1, a(p+2)=p-2; for k>0, a(A049591(k)+3)=A049591(k)-3 etc. - Benoit Cloitre (benoit7848c(AT)orange.fr), Oct 24 2002
|
|
EXAMPLE
|
a(8) = 6 as 8*9*10*11*12*13 is not divisible by 2*3*5*7 but 8*9*10*11*12*13*14 is.
|
|
PROGRAM
|
(PARI) a(n)=if(n<0, 0, k=0; while(prod(i=0, k, n+i)%prod(v=1, precprime(n), if(isprime(v), v, 1))>0, k++); k)
|
|
CROSSREFS
|
Sequence in context: A075348 A055631 A004560 this_sequence A147965 A167542 A167419
Adjacent sequences: A076978 A076979 A076980 this_sequence A076982 A076983 A076984
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Oct 23 2002
|
|
EXTENSIONS
|
More terms from Benoit Cloitre (benoit7848c(AT)orange.fr), Oct 24 2002
|
|
|
Search completed in 0.002 seconds
|
