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A120535
Semiprimes that are not the sum of 3 pentagonal numbers.
0
4, 9, 21, 26, 33, 38, 55, 65, 77, 111, 142, 159, 166, 183, 205, 217, 226, 265, 346, 371, 395, 417, 453, 551, 573, 597, 655, 681, 843, 905, 951, 985, 1059, 1165, 1441, 1563, 2033, 2073, 2126, 2361, 2487, 2841, 2991, 3831, 4061, 4601, 8691, 10911
OFFSET
1,1
COMMENTS
Semiprime analog of A117065.
MATHEMATICA
v = #*(3*#-1)/2& @ Range[0, 90]; Select[ Complement[ Range[0, 11000], Union[Total /@ Tuples[{v, v, v}]]], PrimeOmega[#] == 2 &] (* Giovanni Resta, Jun 13 2016 *)
CROSSREFS
A001358 intersect A003679.
Sequence in context: A334261 A290434 A230834 * A146948 A033944 A287143
KEYWORD
fini,full,nonn
AUTHOR
Jonathan Vos Post, Aug 06 2006
EXTENSIONS
Missing a(39) = 2126 from Giovanni Resta, Jun 13 2016
STATUS
approved