id:A160689 - OEIS Search Results

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a(1)=1. a(n) = the smallest positive integer such that d(a(n)) = d(sum{k=1 to n} a(k)), where d(m) = the number of divisors of m.

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1, 2, 2, 2, 8, 2, 2, 8, 2, 2, 8, 2, 2, 8, 2, 21, 5, 6, 6, 15, 3, 6, 8, 6, 2, 10, 12, 6, 12, 2, 10, 22, 8, 6, 34, 6, 6, 22, 8, 6, 8, 2, 2, 6, 8, 8, 2, 6, 15, 31, 6, 2, 6, 8, 6, 2, 2, 6, 10, 2, 6, 6, 15, 13, 6, 2, 6, 8, 2, 8, 6, 10, 6, 10, 8, 8, 6, 8, 6, 10, 8, 2, 2, 10, 2, 10, 6, 2, 38, 10, 6, 10, 8, 10, 8 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`sum{k=1 to n} a(k) = A160690(n). d(A160689(n)) = d(A160690(n)) = A160691(n).`
	MATHEMATICA	`Contribution from Farideh Firoozbakht (mymontain(AT)yahoo.com), May 28 2009: (Start)` `a[1]=1; a[n_]:=a[n]=(s=Sum[a[k], {k, n-1}]; For[m=1, DivisorSigma[0, m]!=` `DivisorSigma[0, s+m], m++ ]; m); Table[a[n], {n, 95}] (End)`
	CROSSREFS	`A160690, A160691` `Sequence in context: A121258 A087421 A132697 this_sequence A137508 A055921 A029605` `Adjacent sequences: A160686 A160687 A160688 this_sequence A160690 A160691 A160692`
	KEYWORD	`nonn`
	AUTHOR	`Leroy Quet (q1qq2qqq3qqqq(AT)yahoo.com), May 24 2009`
	EXTENSIONS	`More terms from Farideh Firoozbakht (mymontain(AT)yahoo.com), May 28 2009`

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Last modified December 18 21:37 EST 2009. Contains 171024 sequences.

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