|
Search: id:A082431
|
|
|
| A082431 |
|
a(n) = the smallest prime p such that there are exactly n sets of consecutive primes, each of which has an arithmetic mean of p. |
|
+0
3
|
|
| 2, 5, 89, 53, 157, 173, 1597, 15233, 8803, 106753, 1570927, 5296771
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
EXAMPLE
|
a(4) = 53 because there are exactly four sets of consecutive primes which have means of 53: {53}, {47,53,59}, {41,...,67} and {31,...,73},
|
|
PROGRAM
|
(PARI) {a(n)= m=2; starting_index=1; k=starting_index; sum_of_primes=0; prime_count=0; sets=0; until( (prime(starting_index)>m) && (sets==n), if( (prime(starting_index)>m) || (sets>n), m=nextprime(m+1); sets=0; starting_index=1; k=starting_index); sum_of_primes=sum_of_primes+prime(k); prime_count++; mean=sum_of_primes/prime_count; if(mean<m, k++, sum_of_primes=0; prime_count=0; starting_index++; k=starting_index; if(mean==m, sets++))); return(m)} (from Rick L. Shepherd (rshepherd2(AT)hotmail.com), Jun 14 2004)
|
|
CROSSREFS
|
Cf. A050221, A050237, A060863, A082370.
Sequence in context: A123978 A120798 A048187 this_sequence A023272 A057978 A093308
Adjacent sequences: A082428 A082429 A082430 this_sequence A082432 A082433 A082434
|
|
KEYWORD
|
more,nonn
|
|
AUTHOR
|
Naohiro Nomoto (n_nomoto(AT)yabumi.com), May 11 2003
|
|
EXTENSIONS
|
Edited by Don Reble (djr(AT)nk.ca), Jun 17 2003
|
|
|
Search completed in 0.002 seconds
|
