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 A081589 Third row of Pascal-(1,5,1) array A081580. 9
 1, 13, 61, 145, 265, 421, 613, 841, 1105, 1405, 1741, 2113, 2521, 2965, 3445, 3961, 4513, 5101, 5725, 6385, 7081, 7813, 8581, 9385, 10225, 11101, 12013, 12961, 13945, 14965, 16021, 17113, 18241, 19405, 20605, 21841, 23113, 24421, 25765, 27145 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (3,-3,1). FORMULA a(n) = 1-6*n+18*n^2. G.f.: (1+5*x)^2/(1-x)^3. MATHEMATICA CoefficientList[Series[(1 + 5 x)^2 / (1 - x)^3, {x, 0, 40}], x] (* Vincenzo Librandi, Aug 09 2013 *) PROG (MAGMA) [1-6*n+18*n^2: n in [0..40]]; // Vincenzo Librandi, Aug 09 2013 (PARI) a(n)=18*n^2-6*n+1 \\ Charles R Greathouse IV, Jun 17 2017 CROSSREFS Cf. A016921, A081590. Sequence in context: A140615 A086361 A119151 * A270449 A139880 A127876 Adjacent sequences:  A081586 A081587 A081588 * A081590 A081591 A081592 KEYWORD easy,nonn AUTHOR Paul Barry, Mar 23 2003 STATUS approved

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Last modified September 17 16:57 EDT 2019. Contains 327136 sequences. (Running on oeis4.)