A128260 -id:A128260 - cp's OEIS frontend

A128259 Inverse Moebius transform of A128229.

1, 2, 1, 1, 2, 1, 2, 1, 3, 1, 1, 0, 0, 4, 1, 2, 3, 1, 0, 5, 1, 1, 0, 0, 0, 0, 6, 1, 2, 1, 3, 1, 0, 0, 7, 1, 1, 2, 1, 0, 0, 0, 0, 8, 1, 2, 1, 0, 4, 1, 0, 0, 0, 9, 1

Offset: 1

Gary W. Adamson, Feb 21 2007

Row sums = sigma(n), A000203: (1, 3, 4, 7, 6, 12, 8,...) A128260 = A128229 * A051731

			First few rows of the triangle are:
1;
2, 1;
1, 2, 1;
2, 1, 3, 1;
1, 0, 0, 4, 1;
2, 3, 1, 0, 5, 1;
...

Cf. A128229, A051731, A000203, A128260.

A051731 * A128229

A128261 a(n) = tau(n) + (n-1)*tau(n-1).

Original entry on oeis.org

1, 3, 6, 9, 14, 14, 26, 18, 35, 31, 42, 28, 74, 30, 60, 65, 82, 40, 110, 44, 124, 88, 90, 54, 195, 79, 108, 114, 170, 66, 242, 68, 196, 136, 140, 149, 326, 78, 156, 164, 322, 90, 338, 92, 270, 274, 186, 104, 483, 153, 304, 210, 314, 114, 436, 228, 452, 232

Offset: 1

Gary W. Adamson, Feb 21 2007

nonn

			a(5) = 14 = (5 + 4 + 0 + 4 + 1), where (5, 4, 0, 4, 1) = row 5 of A128260.

Andrew Howroyd, Table of n, a(n) for n = 1..1000

Row sums of A128260.

Cf. A000005 (tau), A128229, A051731.

Table[DivisorSigma[0,n]+(n-1)DivisorSigma[0,n-1],{n,60}] (* Harvey P. Dale, Sep 17 2020 *)

a(n)={numdiv(n) + if(n > 1, (n-1)*numdiv(n-1))} \\ Andrew Howroyd, Aug 09 2018

Name changed and terms a(11) and beyond from Andrew Howroyd, Aug 09 2018

cp's OEIS Frontend

A128259 Inverse Moebius transform of A128229.

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A128261 a(n) = tau(n) + (n-1)*tau(n-1).

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