|
| |
|
|
A156778
|
|
n*A007504(n)/2 = n*(sum of first n primes)/2
|
|
1
| |
|
|
0, 1, 5, 15, 34, 70, 123, 203, 308, 450, 645, 880, 1182, 1547, 1967, 2460, 3048, 3740, 4509, 5396, 6390, 7476, 8701, 10051, 11556, 13250, 15093, 17064, 19194, 21460, 23895, 26660, 29616, 32802, 36159, 39830, 43686, 47804, 52193, 56823, 61740
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,3
|
|
|
COMMENTS
| For n>0, the sum of the first n primes, A007504(n), has the opposite parity of n (since both increase by an odd amount, and A007504(n)=2 for n=1.
|
|
|
FORMULA
| a(n) = A156780( prime(n))/2, where prime(n) = A000040(n) is the n-th prime.
|
|
|
PROG
| (PARI) vector(80, n, sum(i=1, n, prime(i))*n)/2
|
|
|
CROSSREFS
| Cf. A156780.
Sequence in context: A084288 A083049 A015627 * A072186 A051807 A034052
Adjacent sequences: A156775 A156776 A156777 * A156779 A156780 A156781
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| M. F. Hasler (www.univ-ag.fr/~mhasler), Feb 21 2009
|
| |
|
|
