cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A210450 Numbers n such that 16n + 7 is in A192628.

Original entry on oeis.org

0, 3, 4, 5, 6, 7, 11, 16, 17, 21, 23, 24, 27, 28, 32, 34, 35, 36, 38, 39, 40, 43, 44, 45, 47, 48, 49, 51, 53, 54, 55, 56, 59, 60, 63, 65, 67, 68, 69, 70, 72, 73, 74, 76, 77, 79, 81, 82, 85, 86, 89, 93, 96, 97, 98, 100, 102, 103, 105, 106, 107, 109, 110
Offset: 1

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Author

Alexander Riasanovsky, Jan 20 2013

Keywords

Comments

Reduce the elements of A192718 (which are the elements of A192628 congruent to 7 (mod 16)) by subtracting 7 and dividing by 16. In "On the reciprocal of the binary generating function for the sum of divisors", this sequence is precisely the set T.

Crossrefs

Programs

  • Sage
    prec = 2^12
    R = PowerSeriesRing(GF(2), 'q', default_prec = prec)
    q = R.gen()
    sigma = lambda x : 1 if x == 0 else sum(Integer(x).divisors())
    SigmaSeries = sum([sigma(m)*q^m for m in range(prec)])
    SigmaBarSeries = 1/SigmaSeries
    SigmaBarList = SigmaBarSeries.exponents()
    reduced = [(m-7)/16 for m in SigmaBarList if mod(m, 8) == 7]
    print(reduced[:128])
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