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A131984 Where records occur in A106708. 3
1, 4, 6, 8, 10, 12, 18, 20, 24, 30, 36, 48, 60, 84, 90, 120, 168, 180, 240, 336, 360, 420, 480, 540, 600, 660, 720, 840, 1080, 1260, 1440, 1680, 2160, 2520, 3360, 3780, 4200, 4620, 5040, 7560, 9240, 10080, 12600, 13860, 15120, 18480, 20160, 25200, 27720 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Numbers n such that concatenation of proper divisors of n exceeds that of all smaller numbers. Empty concatenation is regarded as 0.

Sequence has many terms in common with A034090 (numbers n such that sum of proper divisors of n exceeds that of all smaller numbers), A034287 (numbers n such that product of divisors of n is larger than for any number less than n), A034288 (product of proper divisors is larger than for any smaller number), A067128 (Ramanujan's largely composite numbers, defined to be n such that d(n) >= d(k) for k = 1 to n-1).

LINKS

Klaus Brockhaus, Table of n, a(n) for n=1..144

PROG

(PARI) {map(n) = local(d); d=divisors(n); if(#d<3, 0, d[1]=""; eval(concat(vecextract(d, concat("..", #d-1)))))} {m=28000; r=-1; for(n=1, m, if(r<(a=map(n)), r=a; print1(n, ", ")))}

CROSSREFS

Cf. A106708, A131983 (records), A034090, A034287, A034288, A067128.

Sequence in context: A194594 A163248 A034288 * A307542 A225510 A131694

Adjacent sequences:  A131981 A131982 A131983 * A131985 A131986 A131987

KEYWORD

nonn,base

AUTHOR

Klaus Brockhaus, Aug 05 2007

STATUS

approved

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Last modified May 24 09:41 EDT 2019. Contains 323529 sequences. (Running on oeis4.)