OFFSET
1,1
COMMENTS
If tau(m-1) + 1 = tau(m) = tau(m+1) - 1, then m must be a square.
All known terms are of the form 2*p, where p is a prime congruent to 91 or -91 modulo 1250. Is this a coincidence?
LINKS
Jianing Song, Table of n, a(n) for n = 1..51
EXAMPLE
165182 is a term since tau(165182^2-1) = 8, tau(165182^2) = 9, tau(165182^2+1) = 10.
PROG
(PARI) isA352974(n) = (n>1) && (numdiv(n^2-1) == numdiv(n^2)-1) && (numdiv(n^2+1) == numdiv(n^2)+1)
CROSSREFS
KEYWORD
nonn,hard
AUTHOR
Jianing Song, Apr 13 2022
STATUS
approved