

A062547


a(n) is least odd integer not a partial sum of 1, 3, ..., a(n1).


3



1, 3, 5, 7, 17, 19, 53, 55, 161, 163, 485, 487, 1457, 1459, 4373, 4375, 13121, 13123, 39365, 39367, 118097, 118099, 354293, 354295, 1062881, 1062883, 3188645, 3188647, 9565937, 9565939, 28697813, 28697815, 86093441, 86093443, 258280325
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OFFSET

0,2


COMMENTS

Oddindexed terms = A048473; evenindexed terms a(2n) = a(2n1)+2;
a(2*n) = A048473(n) and also, for n > 0, a(2*n) = 3*a(2*n1)  4; a(2*n+1) = a(2*n) + 2 = A052919(n+1).


LINKS

Table of n, a(n) for n=0..34.
Index entries for linear recurrences with constant coefficients, signature (1,3,3).


FORMULA

From Bruno Berselli, Jan 28 2011: (Start)
G.f.: (1+4*x+5*x^2)/((1+x)*(13*x^2));
a(n) = a(n1) + 3*a(n2) + 3*a(n3) for n > 2.
a(n) = 2*3^((2*n + (1)^n  1)/4)  (1)^n. (End)


EXAMPLE

Partial sums of 1;3;5 are 1;3;4;5;6;8;9 and 7 is the least missing odd integer, hence the next term is 7.


MATHEMATICA

Table[ 1+ 2 3^Floor[k/2]+2 Mod[k, 2], {k, 0, 36}]
LinearRecurrence[{1, 3, 3}, {1, 3, 5}, 40] (* Harvey P. Dale, Jul 14 2018 *)


CROSSREFS

Cf. A048473, A062548.
Sequence in context: A001259 A248370 A087126 * A125739 A219461 A122853
Adjacent sequences: A062544 A062545 A062546 * A062548 A062549 A062550


KEYWORD

nonn,changed


AUTHOR

Wouter Meeussen, Jun 26 2001


STATUS

approved



