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A206025
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Triangular numbers n whose divisors can be partitioned into three disjoint sets whose sums are all sigma(n)/3.
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0
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120, 780, 2016, 3240, 4560, 5460, 7140, 7260, 9180, 10296, 10440, 12720, 19110, 21528, 23220, 26796, 28680, 28920, 32640, 34980, 37128, 39060, 41328, 49770, 51360, 56280, 61776, 64620, 64980, 73920, 79800, 97020, 100128, 103740, 107880, 114960, 115440, 122760
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OFFSET
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1,1
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COMMENTS
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Divisors of triangular number n = 120 can be partitioned into three disjoint sets whose sums are all sigma(n)/3 and this value is triangular numbers (=120). Are there other such triangular numbers?
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LINKS
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EXAMPLE
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Triangular number 780 is in sequence because sigma(780)/3 = 784 = 4+780 = 2+5+6+10+12+13+15+20+26+30+39+52+60+65+78+156+195 = 1+3+130+260+390 (summands are all divisors of 780).
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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