A345420 Row 3 of array in A345417.

1, -1, 0, 3, -2, -5, 7, 4, -9, 6, -6, 15, -8, -17, 19, -21, 12, -12, 27, -14, -29, 16, -33, 18, 39, -20, -41, 43, 22, -45, 51, -26, 55, 28, 30, -30, 63, -65, 67, -69, 36, -36, -38, -77, 79, 40, -42, -89, 91, 46, -93, 48, -48, -50, 103, -105, 54, -54, 111, -56, -113, -117, 123, -62

Offset

1,4

Links

Table of n, a(n) for n=1..64.

Prog

(Python)
from sympy.core.numbers import igcdex
from sympy import prime
def A345420(n): return igcdex(5, prime(n))[0] # Chai Wah Wu, Jul 01 2021

Crossrefs

Cf. A345417-A345422.

Sequence in context: A209584 A209140 A265903 * A364885 A006369 A097284

Adjacent sequences: A345417 A345418 A345419 * A345421 A345422 A345423

Keyword

sign

Author

N. J. A. Sloane, Jun 19 2021

Status

approved