A368921 - OEIS

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A368921

a(n) = n' - n'', where n' is the arithmetic derivative of n, A003415(n) and n'' is its second arithmetic defivative, A068346(n).

3

0, 0, 1, 1, 0, 1, 4, 1, -4, 1, 6, 1, -16, 1, 3, -4, -48, 1, 11, 1, -20, 3, 12, 1, -4, 3, 7, 0, -48, 1, 30, 1, -96, 5, 18, -4, -32, 1, 11, -16, -4, 1, 40, 1, -64, 23, 15, 1, -128, 5, 6, -4, -36, 1, -27, -16, -4, 9, 30, 1, -4, 1, 19, 31, -448, -3, 60, 1, -84, 11, 58, 1, -64, 1, 23, 39, -96, -3, 70, 1, -192, -108, 42

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OFFSET

0,7

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..16384

FORMULA

a(n) = A003415(n) - A068346(n).

a(n) = A368922(n) + A068346(n).

PROG

(PARI)

A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));

A368921(n) = { my(u=A003415(n)); (u-A003415(u)); };

CROSSREFS

Cf. A003415, A068346, A348329 (positions of 0's), A368922.

Sequence in context: A196757 A193254 A193454 * A322819 A089655 A322820

Adjacent sequences: A368918 A368919 A368920 * A368922 A368923 A368924

KEYWORD

sign

AUTHOR

Antti Karttunen, Jan 10 2024

STATUS

approved