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A119765
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Irregular array where row n is the positive integers which divide the number of terms in all previous rows. a(1)=1.
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1
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1, 1, 1, 2, 1, 2, 4, 1, 7, 1, 3, 9, 1, 2, 3, 4, 6, 12, 1, 2, 3, 6, 9, 18, 1, 2, 3, 4, 6, 8, 12, 24, 1, 2, 4, 8, 16, 32, 1, 2, 19, 38, 1, 2, 3, 6, 7, 14, 21, 42, 1, 2, 5, 10, 25, 50, 1, 2, 4, 7, 8, 14, 28, 56, 1, 2, 4, 8, 16, 32, 64, 1, 71, 1, 73, 1, 3, 5, 15, 25, 75, 1, 3, 9, 27, 81, 1, 2, 43, 86
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,4
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EXAMPLE
| Array begins:
1
1
1,2
1,2,4
1,7
1,3,9
12 terms make up these 6 rows. So row 7 is the divisors of 12, (1,2,3,4,6,12).
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MAPLE
| A119765 := proc(nmax) local a, dvs; a := [1] ; while nops(a) < nmax do dvs := numtheory[divisors](nops(a)) ; a := [op(a), op(dvs) ] ; od ; end: a := A119765(300) ; for i from 1 to nops(a) do printf("%d, ", a[i]) ; od ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jun 23 2006
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PROG
| ;; PLT DrScheme - Joshua Zucker (joshua.zucker(AT)stanfordalumni.org), Jun 21 2006
;; positive-divisors gives the list of divisors of n in decreasing order
(define (A119765 n seq)
(cond
[(= n 0) seq]
[else (A119765 (sub1 n) (append seq (reverse (positive-divisors (length seq)))))]))
(A119765 30 (list 1))
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CROSSREFS
| Sequence in context: A156042 A157751 A177701 * A077901 A105619 A121439
Adjacent sequences: A119762 A119763 A119764 * A119766 A119767 A119768
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KEYWORD
| nonn,tabf
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AUTHOR
| Leroy Quet Jun 18 2006
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EXTENSIONS
| More terms from Joshua Zucker (joshua.zucker(AT)stanfordalumni.org) and R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jun 21 2006
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