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Search: id:A112665
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| A112665 |
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Numbers which can not be expressed as a sum of 2 triangular numbers and a power of 2. |
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+0
2
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| 6222, 18081, 22161, 23428, 27342, 29847, 36115, 44137, 47677, 50211, 52534, 56751, 57220, 64008, 70146, 78210, 79632, 81003, 82396, 83538, 84531, 85603, 92374, 92847, 96441, 96873, 97054, 97461, 103572, 103935, 109045, 119685, 121134
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Sequence proposed by Livio Zucca on it.hobby.enigmi. First prime number appearing is 152539. (Cf. A112625)
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EXAMPLE
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6221 and 6223 are not in the sequence since they can be expressed as 6221 = T(105)+T(32)+2^7 and 6223 = T(93)+T(56)+2^8.
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MATHEMATICA
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tab = Table[1, {i, 30000}]; T[n_] := (n + n^2)/2; Do[n=T[i]+T[j]+2^k; If[1<=n<=30000, tab[[n]]=0], {i, 0, 244}, {j, 0, i}, {k, 0, 14}]; Position[tab, 1] // Flatten
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CROSSREFS
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Cf. A112625.
Adjacent sequences: A112662 A112663 A112664 this_sequence A112666 A112667 A112668
Sequence in context: A068757 A031836 A094494 this_sequence A092726 A028545 A071130
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KEYWORD
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nonn
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AUTHOR
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Giovanni Resta (g.resta(AT)iit.cnr.it), Jan 12 2006
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