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0, 3, 13, 30, 54, 85, 123, 168, 220, 279, 345, 418, 498, 585, 679, 780, 888, 1003, 1125, 1254, 1390, 1533, 1683, 1840, 2004, 2175, 2353, 2538, 2730, 2929, 3135, 3348, 3568, 3795, 4029, 4270, 4518, 4773
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Sequence found by reading the line from 0, in the direction 0, 13... and the parallel line from 3, in the direction 3, 30,..., in the square spiral whose edges have length A195019 and whose vertices are the numbers A195020. - Omar E. Pol, Sep 09 2011
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LINKS
| Index entries for sequences related to linear recurrences with constant coefficients, signature (3,-3,1).
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FORMULA
| a(n)=C(7*n,2)/7,n>=0 - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jan 02 2007
a(n) = A049450(n) + A000217(n). [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Oct 09 2008]
a(n)=3*a(n-1)-3*a(n-2)+a(n-3), with a(0)=0, a(1)=3 and a(2)=13 [From Paolo P. Lava (paoloplava(AT)gmail.com), Jul 29 2009]
a(n)=7*n+a(n-1)-4 (with a(0)=0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Aug 04 2010]
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MAPLE
| [seq(binomial(7*n, 2)/7, n=0..37)]; - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jan 02 2007
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MATHEMATICA
| s=0; lst={s}; Do[s+=n++ +3; AppendTo[lst, s], {n, 0, 6!, 7}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 16 2008]
Array[ #*(7*# - 1)/2 &, 47, 0] # A022264 n*(7 n - 1)/2. [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jul 10 2009]
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CROSSREFS
| Sequence in context: A183436 A154300 A051805 * A097955 A077717 A171517
Adjacent sequences: A022261 A022262 A022263 * A022265 A022266 A022267
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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