id:A139435 - OEIS Search Results

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Largest m<n such that first terms of the Collatz trajectory of m sum up to n; a(n)=0 if no such m exists.

+0
2

0, 0, 2, 0, 1, 4, 4, 1, 6, 2, 4, 8, 4, 8, 10, 2, 2, 12, 8, 4, 14, 8, 2, 16, 4, 8, 18, 16, 8, 20, 16, 4, 22, 4, 20, 24, 16, 16, 26, 8, 4, 28, 14, 16, 30, 10, 8, 32, 28, 10, 34, 16, 13, 36, 24, 32, 38, 16, 20, 40, 15, 32, 42, 12, 20, 44, 32, 8, 46, 40, 28, 48, 20, 32, 50, 32, 44, 52, 26, 20 (list; graph; listen)

	OFFSET	`1,3`
	COMMENT	`a(n) = 0 iff A139436(n) = 0; a(n) > 0 for n > 4;` `a(n) <= A004523(n); a(A008585(n)) = A005843(n).`
	LINKS	`R. Zumkeller, Table of n, a(n) for n = 1..10000` `Eric Weisstein's World of Mathematics, Collatz Problem` `Index entries for sequences related to 3x+1 (or Collatz) problem`
	EXAMPLE	`a(30) = 20: 30 = 20+10;` `a(31) = 16: 31 = 16+8+4+2+1;` `a(32) = 4: 32 = 4+2+1+4+2+1+4+2+1+4+2+1+4;` `a(33) = 22: 33 = 22+11;` `a(34) = 4: 34 = 4+2+1+4+2+1+4+2+1+4+2+1+4+2;` `a(35) = 20: 35 = 20+10+5.`
	CROSSREFS	`Cf. A006370.` `Adjacent sequences: A139432 A139433 A139434 this_sequence A139436 A139437 A139438` `Sequence in context: A124912 A138752 A098689 this_sequence A077909 A128749 A106579`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Apr 21 2008`

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Last modified October 7 14:39 EDT 2008. Contains 144666 sequences.

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