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A281002
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Square array read by antidiagonals downwards: A(n, 1) = second Wieferich prime to base n and A(n, k) = second Wieferich prime to base A(n, k-1) for k > 1.
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3
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OFFSET
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2,1
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LINKS
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EXAMPLE
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Array starts:
3511, 19, 7, 491531, ...
1006003, 11, ...
3511, 19, 7, 491531, ...
20771, 18043, ...
534851, 5, 20771, 18043, ...
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PROG
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(PARI) secondwieftobase(n) = my(i=0); forprime(p=1, , if(Mod(n, p^2)^(p-1)==1, if(i==0, i++, return(p))))
table(rows, cols) = for(x=2, rows+1, my(i=0, w=secondwieftobase(x)); while(i < cols, print1(w, ", "); w=secondwieftobase(w); i++); print(""))
table(2, 3)
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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