A326188 a(n) = A001065(n) - A003557(n), where A001065(n) = the sum of proper divisors of n, and A003557(n) = n divided by its largest squarefree divisor.

-1, 0, 0, 1, 0, 5, 0, 3, 1, 7, 0, 14, 0, 9, 8, 7, 0, 18, 0, 20, 10, 13, 0, 32, 1, 15, 4, 26, 0, 41, 0, 15, 14, 19, 12, 49, 0, 21, 16, 46, 0, 53, 0, 38, 30, 25, 0, 68, 1, 38, 20, 44, 0, 57, 16, 60, 22, 31, 0, 106, 0, 33, 38, 31, 18, 77, 0, 56, 26, 73, 0, 111, 0, 39, 44, 62, 18, 89, 0, 98, 13, 43, 0, 138, 22, 45, 32, 88, 0, 141, 20

Offset: 1

Author

Antti Karttunen, Jul 11 2019

Keywords

• sign

Links

• Antti Karttunen, Table of n, a(n) for n = 1..16384
• Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537

Crossrefs

Cf. A000203, A001065, A003557, A010848, A326187, A326189.

Cf. also A326185.

Programs

PARI

A003557(n) = { my(f=factor(n)); for (i=1, #f~, f[i, 2] = f[i, 2]-1); factorback(f); }; \\ From A003557
A326188(n) = ((sigma(n)-A003557(n))-n);

Formula

a(n) = A326187(n) - n = A000203(n) - A003557(n) - n.

a(n) = A001065(n) - A003557(n).