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 A120286 Numerator of 1/n^2 + 2/(n-1)^2 + 3/(n-2)^2 +...+ (n-1)/2^2 + n. 0
 1, 9, 65, 725, 3899, 28763, 419017, 864669, 7981633, 3586319, 200763407, 2649665993, 34899471137, 176508049513, 356606957297, 12234391348253, 209672027529221, 4012917216669239, 15350275129353301, 15443118015171841 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS p^2 divides a(p-1) for prime p>2. p divides a(p-2) for prime p>3. LINKS Table of n, a(n) for n=1..20. FORMULA a(n) = numerator[Sum[Sum[1/i^2,{i,1,k}],{k,1,n}]]. MATHEMATICA Numerator[Table[Sum[Sum[1/i^2, {i, 1, k}], {k, 1, n}], {n, 1, 30}]] CROSSREFS Cf. A027612, A001008, A007406, A007407. Sequence in context: A339688 A100311 A259242 * A152581 A122733 A118465 Adjacent sequences: A120283 A120284 A120285 * A120287 A120288 A120289 KEYWORD frac,nonn AUTHOR Alexander Adamchuk, Jul 07 2006 STATUS approved

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Last modified December 5 00:12 EST 2023. Contains 367565 sequences. (Running on oeis4.)