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A129645 a(1) = 1; for n>1, a(n) = a(n-1)*b(n-1) + 1, where {b(k)} is the concatenated list of the ordered positive divisors of the terms of {a(k)}. 2
1, 2, 3, 7, 8, 25, 26, 183, 184, 369, 1477, 11817, 11818, 59091, 1477276, 1477277, 2954555, 38409216, 998639617, 998639618, 2995918855, 182751050156, 33443442178549, 33443442178550, 66886884357101, 267547537428405 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..26.

EXAMPLE

The list of positive divisors of the terms of {a(k)} is (sequence A129646) 1; 1,2; 1,3; 1,7; 1,2,4,8; .... The n-th term of {a(k)} is a(n-1)*A129646(n-1) +1.

MAPLE

aklist := [] ;

A129645 := proc(n)

    option remember;

    global aklist ;

    local prev;

    if n = 1 then

        return 1;

    else

        prev := procname(n-1) ;

        sort([op(numtheory[divisors](prev))]) ;

        aklist := [op(aklist), op(%)] ;

        return  prev*op(n-1, aklist)+1 ;

    end if;

end proc:

seq(A129645(n), n=1..26) ; # R. J. Mathar, Aug 24 2013

CROSSREFS

Cf. A129646.

Sequence in context: A045545 A029790 A206725 * A112994 A056036 A056432

Adjacent sequences:  A129642 A129643 A129644 * A129646 A129647 A129648

KEYWORD

nonn

AUTHOR

Leroy Quet, Apr 25 2007

EXTENSIONS

More terms from Sean A. Irvine, May 19 2010; corrected (based on the ordered lists of divisors) by Franklin T. Adams-Watters, Aug 24 2013

STATUS

approved

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Last modified February 22 05:17 EST 2019. Contains 320385 sequences. (Running on oeis4.)