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 A106388 Numbers k such that 11k = 6j^2 + 6j + 1. 4
 11, 23, 131, 167, 383, 443, 767, 851, 1283, 1391, 1931, 2063, 2711, 2867, 3623, 3803, 4667, 4871, 5843, 6071, 7151, 7403, 8591, 8867, 10163, 10463, 11867, 12191, 13703, 14051, 15671, 16043, 17771, 18167, 20003, 20423, 22367, 22811, 24863, 25331, 27491, 27983 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS j sequence = A106387 LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 Index entries for linear recurrences with constant coefficients, signature (1,2,-2,-1,1). FORMULA a(1)=11, a(2)=23; if n odd a(n)=a(n-1)+54*(n-1), if n even a(n)=a(n-1)+12*(n-1). a(n) = (66*n*(n-1)-21*(2*n-1)*(-1)^n+23)/4. G.f.:  x*(11+12*x+86*x^2+12*x^3+11*x^4)/((1+x)^2*(1-x)^3). a(n)-a(n-1)-2*a(n-2)+2*a(n-3)+a(n-4)-a(n-5) = 0 for n>5. MATHEMATICA LinearRecurrence[{1, 2, -2, -1, 1}, {11, 23, 131, 167, 383}, 50] (* Harvey P. Dale, Jul 26 2018 *) PROG (PARI) Vec((11+12*x+86*x^2+12*x^3+11*x^4)/(1+x)^2/(1-x)^3+O(x^99)) \\ Charles R Greathouse IV, Dec 28 2011 CROSSREFS Cf. A106387, A106389, A106390. Sequence in context: A288406 A014874 A027899 * A171068 A091465 A261352 Adjacent sequences:  A106385 A106386 A106387 * A106389 A106390 A106391 KEYWORD nonn,easy AUTHOR Pierre CAMI, May 01 2005 EXTENSIONS Formulae corrected and added by Bruno Berselli, Nov 16 2010 More terms from Colin Barker, Apr 16 2014 STATUS approved

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Last modified June 24 05:21 EDT 2019. Contains 324318 sequences. (Running on oeis4.)