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A073932
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Define f(n) = n - largest nontrivial divisor of n or f(n) = n-1 if n is a prime. Form a triangle in which the n-th row contains terms n, f(n), f(f(n), ... until a 1 is reached; sequence gives triangle read by rows.
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4
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1, 2, 1, 3, 2, 1, 4, 2, 1, 5, 4, 2, 1, 6, 3, 2, 1, 7, 6, 3, 2, 1, 8, 4, 2, 1, 9, 6, 3, 2, 1, 10, 5, 4, 2, 1, 11, 10, 5, 4, 2, 1, 12, 6, 3, 2, 1, 13, 12, 6, 3, 2, 1, 14, 7, 6, 3, 2, 1, 15, 10, 5, 4, 2, 1, 16, 8, 4, 2, 1, 17, 16, 8, 4, 2, 1, 18, 9, 6, 3, 2, 1, 19, 18, 9, 6, 3, 2, 1, 20, 10, 5, 4, 2, 1
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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EXAMPLE
| Triangle begins:
1
2 1
3 2 1
4 2 1
5 4 2 1
6 3 2 1
7 6 3 2 1
8 4 2 1
9 6 3 2 1
10 5 4 2 1
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MAPLE
| j := 1:a[1] := 1:for i from 2 to 50 do n := i:j := j+1:a[j] := n:while(n>1) do if isprime(n) then r := n-1: else r := n-n/ifactors(n)[2][1][1]; fi; n := r:j := j+1:a[j] := n: od:od:seq(a[k], k=1..j);
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CROSSREFS
| Cf. A073933, A073934, A073935.
Sequence in context: A128260 A083368 A112379 * A082404 A120885 A193278
Adjacent sequences: A073929 A073930 A073931 * A073933 A073934 A073935
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KEYWORD
| nonn,tabf
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AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Aug 19 2002
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EXTENSIONS
| More terms from Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Aug 23 2002
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