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A235332
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a(n) = n*(9*n + 25)/2 + 6.
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8
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6, 23, 49, 84, 128, 181, 243, 314, 394, 483, 581, 688, 804, 929, 1063, 1206, 1358, 1519, 1689, 1868, 2056, 2253, 2459, 2674, 2898, 3131, 3373, 3624, 3884, 4153, 4431, 4718, 5014, 5319, 5633, 5956, 6288, 6629, 6979, 7338, 7706, 8083, 8469, 8864, 9268, 9681
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OFFSET
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0,1
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COMMENTS
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This is the case d=6 of n*(9*n + 4*d + 1)/2 + d. Other similar sequences are:
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LINKS
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FORMULA
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G.f.: (6 + 5*x - 2*x^2)/(1 - x)^3.
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3).
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MATHEMATICA
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Table[n (9 n + 25)/2 + 6, {n, 0, 50}]
LinearRecurrence[{3, -3, 1}, {6, 23, 49}, 50] (* Harvey P. Dale, Feb 12 2022 *)
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PROG
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(Magma) [n*(9*n+25)/2+6: n in [0..50]];
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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