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A121229 Beginning with a(1) = 1 and a(2) = 2, a(n) is not equal to the product of two consecutive (distinct) earlier terms. 5
1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

N. J. A. Sloane, Table of n, a(n) for n = 1..10000

MAPLE

A121299 := proc(n)

    option remember;

    local a, ispr, i;

    if n <=2 then

        n;

    else

        for a from procname(n-1)+1 do

            ispr := false ;

            for i from 1 to n-2 do

                if procname(i)*procname(i+1) = a then

                    ispr := true ;

                    break;

                end if;

            end do:

            if not ispr then

                return a;

            end if;

        end do:

    end if;

end proc: # R. J. Mathar, May 25 2017

CROSSREFS

Cf. A005228, A030124.

The complement is A286290, excluding the initial 1.

Sequence in context: A267304 A002855 A175233 * A286291 A286926 A145198

Adjacent sequences:  A121226 A121227 A121228 * A121230 A121231 A121232

KEYWORD

easy,nonn

AUTHOR

Giovanni Teofilatto, Aug 21 2006

STATUS

approved

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Last modified August 23 11:41 EDT 2017. Contains 290995 sequences.