login
A363637
Indices of numbers of the form k^2-1, k >= 2, that can be written as a product of smaller numbers of that same form.
1
5, 11, 19, 26, 29, 31, 41, 55, 65, 71, 89, 99, 109, 127, 131, 134, 151, 155, 161, 181, 191, 209, 239, 244, 251, 265, 271, 274, 287, 289, 305, 323, 341, 349, 351, 379, 419, 449, 461, 485, 491, 505, 511, 551, 575, 599, 647, 649, 701, 703, 755, 769, 811, 846, 869
OFFSET
1,1
EXAMPLE
5 is a term because 5^2-1 = 24 = 3*8 = (2^2-1)*(3^2-1)
26 is a term because 26^2-1 = 675 = 3*15*15 = (2^2-1)*(4^2-1)^2. (This is the first term that requires more than two factors.)
CROSSREFS
Sequence in context: A114269 A124855 A286690 * A190756 A022823 A094693
KEYWORD
nonn
AUTHOR
STATUS
approved