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A333913
Numbers k such that lambda(k) is not the sum of 3 squares, where lambda is the Carmichael lambda function (A002322).
2
29, 58, 61, 87, 113, 116, 122, 143, 145, 155, 157, 169, 174, 175, 183, 225, 226, 232, 235, 241, 244, 286, 290, 305, 310, 314, 317, 325, 338, 339, 348, 349, 350, 366, 371, 385, 395, 403, 427, 429, 435, 449, 450, 452, 464, 465, 470, 471, 477, 482, 488, 493, 495
OFFSET
1,1
COMMENTS
Pollack (2011) proved that this sequence has a lower and an upper asymptotic densities, and conjectured that they do not coincide.
LINKS
EXAMPLE
1 is not a term since lambda(1) = 1 = 0^2 + 0^2 + 1^2 is the sum of 3 squares.
29 is a term since lambda(29) = 28 is not the sum of 3 squares.
MATHEMATICA
Select[Range[500], SquaresR[3, CarmichaelLambda[#]] == 0 &]
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Apr 09 2020
STATUS
approved