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A359963 Arithmetic numbers (A003601) having more divisors than all smaller arithmetic numbers. 4
1, 3, 6, 20, 30, 60, 168, 420, 840, 1980, 2160, 2520, 7560, 10080, 15120, 27720, 79200, 83160, 110880, 166320, 262080, 332640, 554400, 786240, 831600, 1081080, 1441440, 2162160, 2882880, 4324320, 7207200, 8648640, 10810800, 17297280, 21621600, 36756720, 43243200 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
The corresponding numbers of divisors are 1, 2, 4, 6, 8, 12, 16, 24, 32, ... .
This sequence is infinite since there are arithmetic numbers with any number of divisors (see A359965).
LINKS
MATHEMATICA
seq[nmax_] := Module[{s = {}, dm = 0, d}, Do[d = DivisorSigma[0, n]; If[d > dm && Divisible[DivisorSigma[1, n], d], dm = d; AppendTo[s, n]], {n, 1, nmax}]; s]; seq[10^6]
PROG
(PARI) lista(nmax) = {my(dm = 0, d); for(n = 1, nmax, d = numdiv(n); if(d > dm && sigma(n)%d == 0, dm = d; print1(n, ", "))); }
CROSSREFS
Subsequence of A003601.
Similar sequences: A002182, A335317, A359964.
Sequence in context: A355605 A356912 A176993 * A276748 A339639 A081181
KEYWORD
nonn
AUTHOR
Amiram Eldar, Jan 20 2023
STATUS
approved

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Last modified April 16 08:27 EDT 2024. Contains 371698 sequences. (Running on oeis4.)