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A340580
Ramanujan's highly composite numbers A002182 sandwiched between nonprimes.
1
120, 1680, 25200, 27720, 50400, 83160, 221760, 277200, 554400, 720720, 2162160, 2882880, 3603600, 7207200, 8648640, 10810800, 17297280, 21621600, 36756720, 73513440, 122522400, 147026880, 245044800, 294053760, 551350800, 2095133040, 2327925600, 2793510720, 3491888400
OFFSET
1,1
EXAMPLE
120 is in the sequence because it is an highly composite numbers A002182 and its nearest neighbors 119 and 121 both are nonprimes.
MATHEMATICA
s = {}; dm = 0; Do[d = DivisorSigma[0, n]; If[d > dm, dm = d; If[! PrimeQ[n - 1] && ! PrimeQ[n + 1], AppendTo[s, n]]], {n, 1, 10^6}]; s (* Amiram Eldar, Aug 17 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Omar E. Pol, Aug 17 2021
EXTENSIONS
More terms from Amiram Eldar, Aug 17 2021
STATUS
approved