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A064808
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The (n+1)st (n+2)-gonal number.
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11
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1, 3, 9, 22, 45, 81, 133, 204, 297, 415, 561, 738, 949, 1197, 1485, 1816, 2193, 2619, 3097, 3630, 4221, 4873, 5589, 6372, 7225, 8151, 9153, 10234, 11397, 12645, 13981, 15408, 16929, 18547, 20265, 22086, 24013, 26049, 28197, 30460, 32841, 35343
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Sum of n terms of the arithmetic progression with first term 1 and common difference n-1. - Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Aug 04 2005
a(n) = sum of row (n+1)-th row terms of triangle A144693. [From Gary W. Adamson (qntmpkt(AT)yahoo.com), Sep 19 2008]
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LINKS
| Harry J. Smith, Table of n, a(n) for n=0,...,1000
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FORMULA
| a(n)=(n+1)(n^2+2)/2
a(n)=sum{k=0..n, sum{j=0..n, (k-(k-1)*C(0, j-k)}}; a(n)=A006002(n)-A000096(n-2). - Paul Barry (pbarry(AT)wit.ie), Nov 18 2005
G.f.: (1-x+3x^2)/(1-x)^4. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 07 2009]
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PROG
| (PARI) { for (n=0, 1000, write("b064808.txt", n, " ", (n + 1)*(n^2 + 2)/2) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Sep 26 2009]
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CROSSREFS
| Main diagonal of A057145.
A144693 [From Gary W. Adamson (qntmpkt(AT)yahoo.com), Sep 19 2008]
Sequence in context: A063586 A131477 A002128 * A192389 A187053 A001937
Adjacent sequences: A064805 A064806 A064807 * A064809 A064810 A064811
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KEYWORD
| easy,nonn
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AUTHOR
| Floor van Lamoen (fvlamoen(AT)hotmail.com), Oct 22 2001
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