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A226120
Decimal expansion of Sum_{n>=1} n^3/(exp(2*Pi*n/7)-1).
1
1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 9, 0, 1, 6, 1, 7, 6, 7, 8, 8, 8, 6, 6, 2, 6, 7, 5, 5, 8, 4, 3, 5, 9, 3, 0, 5, 8, 5, 5, 4, 4, 5, 3, 3, 3, 4, 8, 0, 2, 5, 4, 8, 9, 7, 8, 4, 3, 4, 0, 6, 1, 0, 9, 9, 4, 3, 8, 7, 3, 7, 8, 5, 0, 6, 7, 1, 4, 8, 0, 1, 7, 9, 1, 6, 2, 7, 1, 3, 6, 6, 2, 1
OFFSET
2,19
COMMENTS
An almost-integer discovered by Simon Plouffe. The computed sum equals 10 within 15 digits.
LINKS
Eric Weisstein's MathWorld, Almost Integer
EXAMPLE
10.00000000000000019016176788866267558435930585544533348025489784340610994387...
MATHEMATICA
NSum[n^3/(Exp[2*Pi*n/7] - 1), {n, 1, Infinity}, NSumTerms -> 220, WorkingPrecision -> 100] // RealDigits[#, 10, 100] & // First
CROSSREFS
Cf. A060295 (famous almost-integer: Ramanujan's constant), A226121 (another surprising almost-integer by Simon Plouffe), A007775, A089034.
Sequence in context: A345738 A197070 A197333 * A244593 A335415 A277524
KEYWORD
nonn,cons
AUTHOR
EXTENSIONS
Offset corrected by Rick L. Shepherd, Jan 01 2014
STATUS
approved