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 A139606 a(n) = 15*n + 6. 7
 6, 21, 36, 51, 66, 81, 96, 111, 126, 141, 156, 171, 186, 201, 216, 231, 246, 261, 276, 291, 306, 321, 336, 351, 366, 381, 396, 411, 426, 441, 456, 471, 486, 501, 516, 531, 546, 561, 576, 591, 606, 621, 636, 651, 666, 681, 696, 711, 726, 741, 756, 771, 786 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Numbers of the 6th column of positive numbers in the square array of nonnegative and polygonal numbers A139600. 6th transversal numbers (or 6-transversal numbers): (A000217(6)-6)*n + 6. REFERENCES A. H. Beiler, Recreations in the Theory of Numbers, Dover, NY, 1964, p. 189. - From N. J. A. Sloane, Dec 01 2012 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..5000 Index entries for linear recurrences with constant coefficients, signature (2,-1). FORMULA a(n) = A057145(n+2,6). G.f.: 3*(2+3*x)/(x-1)^2 . - R. J. Mathar, Jul 28 2016 MATHEMATICA Range[6, 1000, 15] (* Vladimir Joseph Stephan Orlovsky, May 31 2011 *) PROG (PARI) a(n)=15*n+6 \\ Charles R Greathouse IV, Oct 05 2011 (MAGMA) [15*n+6 : n in [0..60]]; // Vincenzo Librandi, Oct 06 2011 CROSSREFS Cf. A144562, A153238, A067076. Sequence in context: A256866 A115702 A003340 * A047717 A089982 A151943 Adjacent sequences:  A139603 A139604 A139605 * A139607 A139608 A139609 KEYWORD easy,nonn AUTHOR Omar E. Pol, Apr 27 2008 STATUS approved

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Last modified July 15 16:09 EDT 2019. Contains 325049 sequences. (Running on oeis4.)