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 A244472 2nd-largest term in n-th row of Stern's diatomic triangle A002487. 5
 1, 2, 4, 7, 12, 19, 31, 50, 81, 131, 212, 343, 555, 898, 1453, 2351, 3804, 6155, 9959, 16114, 26073, 42187, 68260, 110447, 178707, 289154, 467861, 757015, 1224876, 1981891, 3206767, 5188658, 8395425, 13584083, 21979508, 35563591, 57543099 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Colin Barker, Table of n, a(n) for n = 1..1000 Jennifer Lansing, Largest Values for the Stern Sequence, J. Integer Seqs., 17 (2014), #14.7.5. Index entries for linear recurrences with constant coefficients, signature (1,1). FORMULA a(n) = A013655(n-1), n>3. a(n) = a(n-1)+a(n-2), n>5. - Colin Barker, Jul 10 2015 G.f.: -x*(x^4+x^3+x^2+x+1) / (x^2+x-1). - Colin Barker, Jul 10 2015 MAPLE A244472 := proc(n) if n < 4 then op(n, [1, 2, 4]) ; else combinat[fibonacci](n+2)-combinat[fibonacci](n-3) ; end if; end proc: seq(A244472(n), n=1..50) ; # R. J. Mathar, Jul 05 2014 MATHEMATICA CoefficientList[Series[-(x^4 + x^3 + x^2 + x + 1)/(x^2 + x - 1), {x, 0, 50}], x] (* Wesley Ivan Hurt, Jul 10 2015 *) Join[{1, 2, 4}, LinearRecurrence[{1, 1}, {7, 12}, 50]] (* Vincenzo Librandi, Jul 11 2015 *) PROG (PARI) Vec(-x*(x^4+x^3+x^2+x+1)/(x^2+x-1) + O(x^100)) \\ Colin Barker, Jul 10 2015 (Magma) I:=[1, 2, 4, 7, 12]; [n le 5 select I[n] else Self(n-1)+Self(n-2): n in [1..40]]; // Wesley Ivan Hurt, Jul 10 2015 CROSSREFS Cf. A002487, A013655, A100545 (bisection). Cf. A244473, A244474, A244475, A244476. Sequence in context: A342229 A326080 A287525 * A279890 A018147 A125892 Adjacent sequences: A244469 A244470 A244471 * A244473 A244474 A244475 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Jul 01 2014 STATUS approved

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Last modified June 4 14:20 EDT 2023. Contains 363128 sequences. (Running on oeis4.)