A024214 a(n) = 4th elementary symmetric function of first n+3 positive integers congruent to 1 mod 3.

280, 5714, 45474, 227969, 859369, 2662569, 7141953, 17147823, 37702863, 77161513, 148781633, 272796342, 479082422, 810530182, 1327228182, 2111584722, 3274516506, 4962843396, 7368036676, 10736476751, 15381384711, 21696600695

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..10000

Index entries for linear recurrences with constant coefficients, signature (9,-36,84,-126,126,-84,36,-9,1).

Formula

a(n) = n*(n+1)*(n+2)*(n+3)*(405*n^4+3510*n^3+9855*n^2+8814*n-184)/1920.

G.f. -x*(280+3194*x+4128*x^2+887*x^3+16*x^4) / (x-1)^9 . - R. J. Mathar, Oct 08 2011

Prog

(Magma) [n*(n+1)*(n+2)*(n+3)*(405*n^4+3510*n^3+9855*n^2+8814*n-184)/1920: n in [1..30]]; // Vincenzo Librandi, Oct 10 2011

Crossrefs

Sequence in context: A327948 A187384 A297724 * A357248 A094895 A223107

Adjacent sequences: A024211 A024212 A024213 * A024215 A024216 A024217

Keyword

nonn,easy

Author

Clark Kimberling

Status

approved