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1, 1, 7, 25, 61, 121, 211, 337, 505, 721, 991, 1321, 1717, 2185, 2731, 3361, 4081, 4897, 5815, 6841, 7981, 9241, 10627, 12145, 13801, 15601, 17551, 19657, 21925, 24361, 26971, 29761, 32737, 35905, 39271, 42841, 46621, 50617, 54835, 59281
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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COMMENTS
| Smallest of n consecutive odd numbers whose sum is n^4. (n^k can be expressed as the sum of n consecutive odd numbers the smallest of which is given by n^(k-1)-n+1.)
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REFERENCES
| T. A. Gulliver, Sequences from Cubes of Integers, Int. Math. Journal, 4 (2003), 439-445.
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LINKS
| Harry J. Smith, Table of n, a(n) for n=0,...,1000
Index to sequences with linear recurrences with constant coefficients, signature (4,-6,4,-1).
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FORMULA
| G.f.: (1-3*x+9*x^2-x^3)/(1 - x)^4. a(-n) = -A126420(n). - Bruno Berselli, Aug 29 2011
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EXAMPLE
| a(5) = 121 = 5^3 - 5 + 1 . We have 121 + 123 + 125 + 127 + 129 = 625 = 5^4.
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PROG
| (PARI) { for (n=0, 1000, write("b061600.txt", n, " ", n^3 - n + 1) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Jul 25 2009]
(MAGMA) [n^3 - n + 1: n in [0..40]]; // Vincenzo Librandi, Aug 29 2011
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CROSSREFS
| Sequence in context: A110672 A162264 A034135 * A098538 A033814 A118395
Adjacent sequences: A061597 A061598 A061599 * A061601 A061602 A061603
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KEYWORD
| nonn,easy
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AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), May 19 2001
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EXTENSIONS
| OFFSET changed from 1,3 to 0,3 by Harry J. Smith (hjsmithh(AT)sbcglobal.net), Jul 25 2009
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