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A326612
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Indices where A001175 (Pisano period) sets a new record value.
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1
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1, 2, 3, 5, 6, 10, 25, 30, 50, 98, 125, 150, 206, 243, 250, 490, 566, 590, 625, 750, 1030, 1046, 1094, 1154, 1214, 1226, 1250, 2450, 2738, 2830, 2846, 2894, 2906, 3086, 3125, 3750, 4802, 5534, 5594, 5606, 5666, 5714, 5770, 5834, 5906, 5990, 6070, 6130, 6250
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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COMMENTS
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Record values: 1, 3, 8, 20, 24, 60, 100, 120, 300, 336, 500, 600, 624, 648, 1500, 1680, 1704, 1740, 2500, 3000, ...
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LINKS
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PROG
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(PARI) fibmod(n, m)=((Mod([1, 1; 1, 0], m))^n)[1, 2]
entryp(p)=my(k=p+[0, -1, 1, 1, -1][p%5+1], f=factor(k)); for(i=1, #f[, 1], for(j=1, f[i, 2], if((Mod([1, 1; 1, 0], p)^(k/f[i, 1]))[1, 2], break); k/=f[i, 1])); k
entry(n)=if(n==1, return(1)); my(f=factor(n), v); v=vector(#f~, i, if(f[i, 1]>1e14, entryp(f[i, 1]^f[i, 2]), entryp(f[i, 1])*f[i, 1]^(f[i, 2] - 1))); if(f[1, 1]==2&&f[1, 2]>1, v[1]=3<<max(f[1, 2]-2, 1)); lcm(v)
a(n)=if(n==1, return(1)); my(k=entry(n)); forstep(i=k, n^2, k, if(fibmod(i-1, n)==1, return(i)))
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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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