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A024378
a(n) = 2nd elementary symmetric function of the first n+1 positive integers congruent to 1 mod 4.
5
5, 59, 254, 730, 1675, 3325, 5964, 9924, 15585, 23375, 33770, 47294, 64519, 86065, 112600, 144840, 183549, 229539, 283670, 346850, 420035, 504229, 600484, 709900, 833625, 972855, 1128834, 1302854, 1496255, 1710425, 1946800, 2206864, 2492149
OFFSET
1,1
FORMULA
a(n) = n*(n+1)*(12*n^2+8*n-5)/6.
G.f.: -x*(5+34*x+9*x^2) / (x-1)^5. - R. J. Mathar, Oct 08 2011
MAPLE
A024378:=n->n*(n+1)*(12*n^2+8*n-5)/6: seq(A024378(n), n=1..50); # Wesley Ivan Hurt, Apr 27 2017
CROSSREFS
Sequence in context: A179028 A179029 A049079 * A362535 A112461 A222585
KEYWORD
nonn,easy
STATUS
approved