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 A243700 The lexicographically earliest sequence of distinct terms with a(1) = 1 such that a(n) divides the sum of the first a(n) terms. 9
 1, 3, 2, 5, 9, 7, 8, 13, 15, 11, 14, 16, 26, 24, 41, 29, 18, 28, 20, 30, 22, 32, 25, 33, 43, 45, 31, 37, 50, 52, 54, 56, 58, 35, 87, 38, 55, 67, 40, 60, 72, 44, 63, 77, 79, 47, 70, 49, 121, 88, 53, 129, 94, 96, 98, 100, 59, 89, 105, 107, 62, 158, 113, 65, 102, 68, 103, 189 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Once there is a k such that k > n and a(k) > n, n can no longer appear in the sequence, otherwise a(k) would be n. - Franklin T. Adams-Watters, Jun 11 2014 If the sum a(1) + a(2) + ... + a(m) is not divisible by m, then m does not belong to this sequence. Sequence A019444 gives a variant of this sequence, where every positive integer is a term. - Max Alekseyev, Jun 11 2014 Positive integers that do not appear in this sequence form A243864. Is there any index n > 3 such that a(n) <= n ? - Max Alekseyev, Jun 13 2014 REFERENCES Eric Angelini, Posting to the Sequence Fans Mailing List, Jun 11 2014 LINKS Max Alekseyev, Table of n, a(n) for n = 1..100000 (first 1100 terms from Jean-Marc Falcoz) EXAMPLE 1 divides the sum of the first 1 term  (yes:  1/1=1) 3 divides the sum of the first 3 terms (yes:  6/3=2) 2 divides the sum of the first 2 terms (yes:  4/2=2) 5 divides the sum of the first 5 terms (yes: 20/5=4) 9 divides the sum of the first 9 terms (yes: 63/9=7) 7 divides the sum of the first 7 terms (yes: 35/7=5) 8 divides the sum of the first 8 terms (yes: 48/8=6) ... PROG (PARI) { printA243700() = my( S=Set(), T=[], s=0, m=1, k); for(n=1, 10^5, k=m; while( ((k==n || setsearch(S, n)) && Mod(s+k, n)) || if(k

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Last modified September 29 04:06 EDT 2020. Contains 337420 sequences. (Running on oeis4.)