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A255413
a(n) = 15*n - 11 + (n mod 2). Row 3 of Ludic array A255127.
8
5, 19, 35, 49, 65, 79, 95, 109, 125, 139, 155, 169, 185, 199, 215, 229, 245, 259, 275, 289, 305, 319, 335, 349, 365, 379, 395, 409, 425, 439, 455, 469, 485, 499, 515, 529, 545, 559, 575, 589, 605, 619, 635, 649, 665, 679, 695, 709, 725, 739, 755, 769, 785, 799, 815, 829, 845, 859, 875, 889, 905, 919, 935, 949, 965, 979, 995, 1009
OFFSET
1,1
FORMULA
a(n) = A007310((5*n)-3).
a(n) = A255407(A084967(n)) = A255407(5*A007310(n)).
a(2n+1) = 5*A016921(n) for all n >= 0.
From M. F. Hasler, Nov 09 2024: (Start)
a(n) = a(n-1) + a(n-2) + a(n-3) for n > 3, a(1..3) = (5, 19, 35).
a(n) = a(n-2) + 30 for n > 2, with a(1..2) = (5, 19).
a(2n-1) = 30n - 25, a(2n) = 30n - 11.
G.f.: x*(5 + 14*x + 11*x^2)/((1 - x)^2*(1 + x)). (End)
E.g.f.: 11 + (15*x - 11)*cosh(x) + 5*(3*x - 2)*sinh(x). - Stefano Spezia, Nov 12 2024
MATHEMATICA
a[n_] := 15 n + Mod[n, 2] - 11;
Array[a, 100] (* Jean-François Alcover, Mar 14 2016 *)
PROG
(Scheme) ;; two alternatives:
(define (A255413 n) (A255127bi 3 n)) ;; Code for A255127bi given in A255127.
(define (A255413 n) (A007310 (- (* 5 n) 3)))
(PARI) apply( {A255413(n)=15*n-11+n%2}, [1..50]) \\ M. F. Hasler, Nov 09 2024
CROSSREFS
Row 3 of A255127.
Sequence in context: A252930 A031019 A324557 * A031041 A029523 A289289
KEYWORD
nonn,easy
AUTHOR
Antti Karttunen, Feb 22 2015
EXTENSIONS
New definition from M. F. Hasler, Nov 09 2024
STATUS
approved