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A080712 a(0) = 4; for n>0, a(n) is taken to be the smallest positive integer greater than a(n-1) which is consistent with the condition "n is a member of the sequence if and only if a(n) is a multiple of 3". 2
4, 5, 7, 8, 9, 12, 13, 15, 18, 21, 22, 23, 24, 27, 28, 30, 31, 32, 33, 34, 35, 36, 39, 42, 45, 46, 47, 48, 51, 52, 54, 57, 60, 63, 66, 69, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 84, 87, 90, 91, 92, 93, 96, 97, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..66.

B. Cloitre, N. J. A. Sloane and M. J. Vandermast, Numerical analogues of Aronson's sequence, J. Integer Seqs., Vol. 6 (2003), #03.2.2.

B. Cloitre, N. J. A. Sloane and M. J. Vandermast, Numerical analogues of Aronson's sequence (math.NT/0305308)

Index entries for sequences of the a(a(n)) = 2n family

FORMULA

a(a(n)) = 3*(n+3).

PROG

(PARI) {a=4; m=[4]; for(n=1, 67, print1(a, ", "); a=a+1; if(m[1]==n, while(a%3>0, a++); m=if(length(m)==1, [], vecextract(m, "2..")), if(a%3==0, a++)); m=concat(m, a))}

CROSSREFS

Cf. A079000, A003605, A079253, A080711, A080710.

Sequence in context: A266267 A189477 A047494 * A005048 A119642 A276705

Adjacent sequences:  A080709 A080710 A080711 * A080713 A080714 A080715

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Mar 05 2003

EXTENSIONS

More terms and PARI code from Klaus Brockhaus, Mar 06 2003

STATUS

approved

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Last modified April 25 21:06 EDT 2019. Contains 322461 sequences. (Running on oeis4.)