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A085076
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Triangular numbers > 0 with a prime signature that has not occurred earlier.
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2
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1, 3, 6, 28, 36, 66, 120, 136, 210, 276, 300, 496, 528, 630, 1176, 2016, 2080, 3240, 3570, 4560, 4950, 5460, 6216, 8128, 8256, 9180, 25200, 29403, 32640, 32896, 37128, 39060, 41328, 41616, 51040, 61776, 64980, 73920, 79800, 93096, 97020, 103740, 115440
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graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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LINKS
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PROG
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(PARI) e=vector(22); for(j=1, 22, e[j]=concat(Str(j), ", ")); ps=vector(1000); c=0; for(m=1, 7388415, t=m*(m+1)\2; om=omega(t); f=factorint(t); v=vector(om); for(j=1, om, v[j]=f[j, 2]); v=vecsort(v, , 4); st=""; for(j=1, om, st=concat(st, e[v[j]])); fd=0; for(j=1, c, if(st==ps[j], fd=1; j=c)); if(fd==0, c++; write("b085076.txt", c " " t); ps[c]=st)) /* Donovan Johnson, May 26 2013 */
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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