login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A024536
[ (4th elementary symmetric function of P(n))/(3rd elementary symmetric function of P(n)) ], where P(n) = {1, p(1), p(2), ..., p(n-1)}, p(0) = 1.
1
0, 1, 2, 4, 7, 10, 14, 19, 25, 32, 40, 49, 59, 70, 82, 95, 110, 125, 141, 159, 178, 197, 219, 242, 265, 290, 315, 341, 370, 400, 432, 464, 498, 534, 570, 608, 647, 688, 730, 773, 818, 863, 910, 957, 1007, 1060, 1114, 1168, 1224, 1281, 1338, 1398
OFFSET
4,3
COMMENTS
p(i) denotes the i-th prime and [...] the floor function. - M. F. Hasler, Dec 11 2007
FORMULA
a(n) = floor(A024524(n)/A024523(n))
PROG
(PARI) /* symmetric polynomial of order n in X=[X1, ..., XN] */ sympol(X, n, s)=forvec(i=vector(n, j, [1, #X]), s+=prod(k=1, n, X[i[k]]), 2); s /* list of primes 0...n-1 with p(0)=1 */ P(n)=concat([1], vector(n-1, i, prime(i))) /* this sequence */ A024536(n) = sympol(P(n), 4) \ sympol(P(n), 3) \\ M. F. Hasler, Dec 11 2007
CROSSREFS
Sequence in context: A025710 A023536 A196126 * A177237 A094281 A076101
KEYWORD
nonn
EXTENSIONS
Extended (up to a(55)) by M. F. Hasler, Dec 11 2007
STATUS
approved