A074644 a(n) = (A074639(n^2) - A074639(n)) mod n.

0, 0, 2, 0, 0, 4, 0, 0, 0, 0, 0, 4, 0, 0, 10, 0, 0, 0, 0, 0, 0, 0, 0, 16, 0, 0, 0, 0, 0, 20, 0, 0, 22, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 16, 0, 0, 34, 0, 0, 0, 0, 0, 0, 0, 0, 20, 0, 0, 0, 0, 0, 44, 0, 0, 46, 0, 0, 0, 0, 0, 25, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 58, 0, 0, 0, 0, 0, 0, 0, 0, 64, 0, 0, 0, 0, 0, 68

Offset

1,3

Links

Antti Karttunen, Table of n, a(n) for n = 1..2500

Prog

(PARI)
A074639(n) = sum(i=1, n-1, if(1==gcd(i, n), (i*(i^(-1) % n)-1)/n)); \\ (after Maple-code in A074639)
A074644(n) = ((A074639(n^2)-A074639(n))%n); \\ Antti Karttunen, Jan 15 2025

Crossrefs

Cf. A074639.

Sequence in context: A389066 A216394 A028590 * A321256 A130123 A319935

Adjacent sequences: A074641 A074642 A074643 * A074645 A074646 A074647

Keyword

nonn

Author

Michele Dondi (bik.mido(AT)tiscalinet.it), Sep 12 2002

Extensions

More terms from Antti Karttunen, Jan 15 2025

Status

approved