A359127 Oblong numbers which are products of six distinct primes.

43890, 53130, 81510, 108570, 152490, 184470, 188790, 260610, 297570, 371490, 416670, 475410, 509082, 549822, 593670, 637602, 648830, 756030, 757770, 814506, 932190, 939930, 973182, 1003002, 1045506, 1135290, 1178310, 1222130, 1233210, 1257762, 1278030, 1332870, 1414910, 1417290, 1484742

Offset: 1

Author

Massimo Kofler, Dec 26 2022

Keywords

• nonn

Examples

			43890 = 209*210 = 2*3*5*7*11*19
53130 = 230*231 = 2*3*5*7*11*23
81510 = 285*286 = 2*3*5*11*13*19
108570 = 329*330 = 2*3*5*7*11*47
		

Crossrefs

Intersection of A002378 and A067885.

Cf. A359304.

Programs

Maple

R:= NULL: count:= 0:
for n from 1 while count < 100 do
  x:= n*(n+1);
  F:= ifactors(x)[2];
  if nops(F) = 6 and max(map(t -> t[2],F))=1 then
     R:= R, x; count:= count+1;
  fi
od:
R; # Robert Israel, Dec 26 2022

Mathematica

Select[(#*(# + 1)) & /@ Range[1250], FactorInteger[#][[;; , 2]] == {1, 1, 1, 1, 1, 1} &] (* Amiram Eldar, Dec 26 2022 *)