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A232180 First bisection of harmonic numbers (numerators). 2
1, 11, 137, 363, 7129, 83711, 1145993, 1195757, 42142223, 275295799, 18858053, 444316699, 34052522467, 312536252003, 9227046511387, 290774257297357, 53676090078349, 54437269998109, 2040798836801833, 2066035355155033, 85691034670497533 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Numerator of H(2n+1), where H(n) = sum_{k=1..n} 1/k.

It can be noted that the second row of the Akiyama-Tanigawa transform of the fractions A232180/A232181 has a simple expression: -5/6, -9/10, -13/14, -17/18, -21/22, ... are of the form -(4*k+5)/(4*k+6).

LINKS

Table of n, a(n) for n=1..21.

FORMULA

a(n) ~ exp(2n).

MATHEMATICA

a[n_] := HarmonicNumber[2*n-1] // Numerator; Table[a[n], {n, 1, 25}]

PROG

(MAGMA) [Numerator(HarmonicNumber(2*n-1)): n in [1..30]]; // Bruno Berselli, Nov 20 2013

CROSSREFS

Cf. A001008, A002547, A093158, A175441, A232181 (denominators).

Sequence in context: A233258 A262382 A142895 * A201111 A124079 A174289

Adjacent sequences:  A232177 A232178 A232179 * A232181 A232182 A232183

KEYWORD

nonn,frac,easy

AUTHOR

Jean-Fran├žois Alcover and Paul Curtz, Nov 20 2013

STATUS

approved

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Last modified April 16 12:45 EDT 2021. Contains 343037 sequences. (Running on oeis4.)