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A024391 2nd elementary symmetric function of the first n+1 positive integers congruent to 2 mod 3. 5
10, 66, 231, 595, 1275, 2415, 4186, 6786, 10440, 15400, 21945, 30381, 41041, 54285, 70500, 90100, 113526, 141246, 173755, 211575, 255255, 305371, 362526, 427350, 500500, 582660, 674541, 776881, 890445, 1016025, 1154440, 1306536, 1473186, 1655290 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..34.

Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).

FORMULA

a(n) = n*(n+1)*(3*n+2)*(3*n+5)/8.

O.g.f.: -x*(10+16*x+x^2)/(-1+x)^5 . - R. J. Mathar, Feb 14 2008

MATHEMATICA

LinearRecurrence[{5, -10, 10, -5, 1}, {10, 66, 231, 595, 1275}, 50] (* Harvey P. Dale, Aug 19 2019 *)

CROSSREFS

Sequence in context: A269679 A211056 A269468 * A074362 A080421 A320817

Adjacent sequences:  A024388 A024389 A024390 * A024392 A024393 A024394

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified August 11 22:58 EDT 2022. Contains 356067 sequences. (Running on oeis4.)