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.

A140255 Inverse Mobius transform of A014963.

Original entry on oeis.org

1, 3, 4, 5, 6, 7, 8, 7, 7, 9, 12, 10, 14, 11, 10, 9, 18, 11, 20, 12, 12, 15, 24, 13, 11, 17, 10, 14, 30, 15, 32, 11, 16, 21, 14, 15, 38, 23, 18, 15, 42, 17, 44, 18, 14, 27, 48, 16, 15, 15, 22, 20, 54, 15, 18, 17, 24, 33, 60, 20, 62, 35, 16, 13, 20, 21, 68, 24, 28, 19, 72, 19, 74
Offset: 1

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Author

Gary W. Adamson and Mats Granvik, May 16 2008

Keywords

Examples

			a(4) = 5 = (1, 1, 0, 1) dot (1, 2, 3, 2) = (1 + 2 + 0 + 2); where (1, 1, 0, 1) = row 4 of triangle A051731 and (1, 2, 3, 2) = the first 4 terms of A014963.
		

Crossrefs

Programs

  • PARI
    expmangoldt(n)=ispower(n, , &n); if(isprime(n), n, 1);
    a(n) = sumdiv(n, d, expmangoldt(d)) \\ Jodi Spitz, Apr 11 2023

Formula

A051731 as an infinite lower triangular matrix * A014963 as a vector.
Equals row sums of triangle A140256. - Gary W. Adamson, May 16 2008
G.f.: Sum_{k>=1} M(k)*x^k/(1 - x^k), where M(k) is the exponential of Mangoldt function (A014963). - Ilya Gutkovskiy, Jan 16 2017

Extensions

More terms from R. J. Mathar, Jan 19 2009