[seqfan] Xenial numbers
юрий герасимов
2stepan at rambler.ru
Thu Jul 16 20:16:17 CEST 2015
Dear SeqFans,
Xenial pairs (sorted by products): (3, 8), (7, 16), (7, 27), (11, 18), (17, 49), (29, 50), (41, 54), (43, 60), (31, 64), (71, 84), (29, 99), (41, 153), (53, 207), (107, 132), (79, 243), (131, 162), (73, 245), (113, 225), (131, 242), (127, 255), (127, 256), (157, 220), (179, 228), ...
A pair of number x and y called xenial if the sum of A069289(x) and A069289(y) is equal to the sum of A008472(x) and A008472(y) where A069859(n) is n*sum( p | n, 1/p ) and A008472(n) is sum( p | n, p }, p prime dividing n.
If x < y, then all x are primes { or bigomga(x) = 1) and bigomega(y) >= 3.
Your sequence is of general interest?
Thanks, JSG
More information about the SeqFan
mailing list