A340194 a(n) = A337544(A003961(n)).

1, 3, 5, 15, 9, 13, 11, 75, 35, 25, 15, 65, 17, 31, 43, 375, 21, 91, 27, 125, 53, 43, 29, 325, 99, 49, 245, 155, 35, 95, 39, 1875, 73, 61, 97, 455, 41, 79, 83, 625, 45, 121, 51, 215, 301, 85, 57, 1625, 143, 275, 103, 245, 59, 637, 133, 775, 133, 103, 65, 475, 69, 115, 371, 9375, 151, 173, 71, 305, 143, 245, 77, 2275, 81, 121

Offset: 1

Author

Antti Karttunen, Dec 31 2020

Keywords

• sign

Comments

First negative term is a(510510) = -686785. See A001276.

Links

• Antti Karttunen, Table of n, a(n) for n = 1..16383
• Index entries for sequences computed from indices in prime factorization

Crossrefs

Cf. A001276, A003961, A003972, A083254, A337544.

Programs

PARI

A003961(n) = my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f);
A083254(n) = (2*eulerphi(n)-n);
A340194(n) = A083254(A003961(A003961(n)));

Formula

a(n) = A337544(A003961(n)) = A083254(A003961(A003961(n))).