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A159354
Decimal expansion of 18 - 24*log(2).
1
1, 3, 6, 4, 4, 6, 7, 6, 6, 6, 5, 6, 1, 3, 1, 2, 5, 7, 3, 9, 8, 6, 4, 2, 9, 0, 8, 5, 0, 0, 3, 7, 6, 2, 3, 6, 6, 1, 8, 7, 9, 9, 6, 7, 7, 5, 3, 5, 3, 8, 7, 3, 9, 0, 1, 1, 0, 3, 6, 7, 9, 7, 7, 2, 1, 5, 8, 5, 5, 3, 0, 7, 2, 7, 2, 7, 3
OFFSET
1,2
COMMENTS
The sum of the reciprocals of the nonnegative square pyramidal numbers (A000330).
LINKS
E. Pérez Herrero, Square Pyramidal Numbers Reciprocals Sum, Psychedelic Geometry Blogspot
pipi, How to evaluate sum_{n>=1} 1/(1^k+2^k+...+n^k) ?, math.stackexchange, Feb 28 2013
FORMULA
Equals Sum_{k>=1} 1/(n*(n+1)*(2*n+1)/6). - Joerg Arndt, Dec 08 2013
MATHEMATICA
Sum[1/Sum[i^2, {i, 1, k}], {k, 1, Infinity}]
RealDigits[18-24*Log[2], 10, 100][[1]] (* G. C. Greubel, Jun 15 2018 *)
PROG
(PARI) 18 - 24*log(2) \\ G. C. Greubel, Jun 15 2018
(Magma) 18 - 24*Log(2); // G. C. Greubel, Jun 15 2018
CROSSREFS
Cf. A000292.
Sequence in context: A006464 A233825 A351124 * A196500 A023676 A318524
KEYWORD
cons,nonn
AUTHOR
STATUS
approved