A345421 Row 4 of array in A345417.

1, 1, -2, 0, -3, 2, 5, -8, 10, -4, 9, 16, 6, -6, -20, -15, 17, -26, -19, -10, 21, 34, 12, -38, 14, 29, -44, 46, -31, -16, -18, -56, -39, 20, 64, -43, 45, 70, 24, -74, -51, 26, 82, -55, -28, 57, -30, 32, 65, -98, 100, -34, 69, 36, -110, -75, 77, -116, -79, -40, 81, 42, 44, 89

Offset: 1

Author

N. J. A. Sloane, Jun 19 2021

Keywords

• sign

Crossrefs

Cf. A345417-A345422.

Programs

Python

from sympy.core.numbers import igcdex
from sympy import prime
def A345421(n): return igcdex(7, prime(n))[0] # Chai Wah Wu, Jul 01 2021