

A199108


a(n) = 4*3^n+1.


2



5, 13, 37, 109, 325, 973, 2917, 8749, 26245, 78733, 236197, 708589, 2125765, 6377293, 19131877, 57395629, 172186885, 516560653, 1549681957, 4649045869, 13947137605, 41841412813, 125524238437, 376572715309, 1129718145925, 3389154437773
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OFFSET

0,1


COMMENTS

An Engel expansion of 3/4 to the base 3 as defined in A181565, with the associated series expansion 3/4 = 3/5 + 3^2/(5*13) + 3^3/(5*13*37) + 3^4/(5*13*37*109) + ....  Peter Bala, Oct 29 2013


LINKS



FORMULA

a(n) = 3*a(n1)2.
a(n) = 4*a(n1)3*a(n2).


MATHEMATICA

4*3^Range[0, 30]+1 (* or *) LinearRecurrence[{4, 3}, {5, 13}, 30] (* or *) NestList[3#2&, 5, 30] (* Harvey P. Dale, Mar 01 2012 *)


PROG

(Magma) [4*3^n+1 : n in [0..30]]


CROSSREFS



KEYWORD

nonn,easy


AUTHOR



STATUS

approved



