

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
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OFFSET

1,2


COMMENTS

The sum of the reciprocals of the nonnegative square pyramidal numbers (A000330).


LINKS

G. C. Greubel, Table of n, a(n) for n = 1..10000
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[1824*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: A308291 A006464 A233825 * A196500 A023676 A318524
Adjacent sequences: A159351 A159352 A159353 * A159355 A159356 A159357


KEYWORD

cons,nonn


AUTHOR

Enrique Pérez Herrero, Apr 11 2009


STATUS

approved



