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A153784
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4 times heptagonal numbers: 2n(5n-3).
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3
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0, 4, 28, 72, 136, 220, 324, 448, 592, 756, 940, 1144, 1368, 1612, 1876, 2160, 2464, 2788, 3132, 3496, 3880, 4284, 4708, 5152, 5616, 6100, 6604, 7128, 7672, 8236, 8820, 9424, 10048, 10692, 11356, 12040, 12744, 13468, 14212, 14976, 15760
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OFFSET
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0,2
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COMMENTS
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Sequence found by reading the line from 0, in the direction 0, 4,..., in the square spiral whose vertices are the generalized heptagonal numbers A085787. - Omar E. Pol, Jul 18 2012
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LINKS
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FORMULA
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a(0)=0, a(1)=4, a(2)=28, a(n)=3*a(n-1)-3*a(n-2)+a(n-3). - Harvey P. Dale, Mar 19 2015
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MATHEMATICA
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Table[2n(5n-3), {n, 0, 40}] (* or *) LinearRecurrence[{3, -3, 1}, {0, 4, 28}, 50] (* Harvey P. Dale, Mar 19 2015 *)
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PROG
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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