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 A255266 Numbers representable in more than one way as x*y*(x+y), where x>=y>1. 0
 240, 390, 810, 880, 1008, 1020, 1680, 1920, 2100, 2310, 2970, 3120, 3360, 3696, 3750, 4320, 4914, 5460, 5670, 6090, 6270, 6480, 6630, 7040, 7380, 7440, 7770, 8064, 8160, 8190, 8448, 8580, 8976, 9240, 9520, 10290, 10530, 10640, 11340, 11856, 12474, 13440, 13776, 14040 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..44. EXAMPLE a(3) = 810 = 15*3*(15+3) = 9*6*(9+6). PROG (Python) TOP = 100000 a = [0]*TOP for y in range(2, TOP//2): for x in range(y, TOP//2): k = x*y*(x+y) if k>=TOP: break a[k]+=1 print([n for n in range(TOP) if a[n]>1]) CROSSREFS Cf. A255265, A081779. Sequence in context: A179644 A099833 A272950 * A179440 A154378 A300145 Adjacent sequences: A255263 A255264 A255265 * A255267 A255268 A255269 KEYWORD nonn AUTHOR Alex Ratushnyak, Feb 19 2015 STATUS approved

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Last modified June 18 01:52 EDT 2024. Contains 373468 sequences. (Running on oeis4.)