A062834 - OEIS

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A062834

Denominator of sum of first n terms of the series 1/3 + 1/8 + 1/24 ... in which the denominators are one less than a perfect square that cannot otherwise be written as a power (cf. A062757, A037450).

3, 24, 2, 70, 1680, 55440, 55440, 65520, 65520, 5040, 10080, 5040, 1627920, 1627920, 85680, 942480, 21677040, 492660, 107100, 64260, 621180, 1242360, 1328040, 10624320, 1328040, 14608440, 1217370, 277560360, 133506533160

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

REFERENCES

W. Dunham, Euler: The Master of Us All, The Mathematical Association of America, Washington D.C., 1999, p. 66.

L. Euler, "Variae observationes circa series infinitas," Opera Omnia, Ser. 1, Vol. 14, pp. 216-244.

LINKS

Table of n, a(n) for n=1..29.

L. Euler, Variae observationes circa series infinitas

MATHEMATICA

Table[ Denominator[ Plus@@(Take[ Select[ Range[ 2, 50 ], GCD@@(Last/@FactorInteger[ # ])==1& ]^2-1, k ]^-1) ], {k, 1, 29} ]

CROSSREFS