|
|
A342567
|
|
a(n) = (prime(n)^2 - prime(n-1)*prime(n+1))/2, n >= 3.
|
|
2
|
|
|
2, -3, 15, -9, 21, -15, -11, 64, -56, 49, 45, -39, -35, 18, 124, -116, 79, 75, -140, 91, -71, -65, 210, 105, -99, 111, -105, -537, 663, -119, 280, -546, 606, -296, 18, 175, -155, 18, 364, -714, 774, -189, 201, -983, 72, 916, 231, -225, -221, 484, -954, 532, 18, 18
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
3,1
|
|
LINKS
|
|
|
FORMULA
|
|
|
PROG
|
(PARI) forprime(p=5, 265, my(pp=precprime(p-1), pn=nextprime(p+1)); print1((p^2-pp*pn)/2, ", "))
(Python)
from primesieve.numpy import n_primes
primesarray = numpy.array(n_primes(10005, 1))
for i in range (2, 10003):
print(((primesarray[i]**2)-(primesarray[i-1]*primesarray[i+1]))//2)
|
|
CROSSREFS
|
|
|
KEYWORD
|
sign,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|