[seqfan] Definition issues with A121240 and A119523

Alonso Del Arte alonso.delarte at gmail.com
Thu Apr 5 07:20:02 CEST 2012

The formula for A119523 (given in a comment) is "Sum_{ k >= 1}
(k)/2^k" (A010051 being the characteristic function of the primes). But my
calculations instead led me to A121240 (the title of which could use a
little de-Mathematica-ization, by the way). To get the value of A119523, it
seems to me that instead of chi_p one should use primepi, and thus
A000720(k)/2^k rather than A010051(k)/2^k in the iterated sum. Just a dozen
iterations are sufficient to get the value to two decimal places. Unless
I've overlooked some small but significant detail.


Alonso del Arte
Author at SmashWords.com<https://www.smashwords.com/profile/view/AlonsoDelarte>
Musician at ReverbNation.com <http://www.reverbnation.com/alonsodelarte>

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