A317716 Square array A(n, k), read by antidiagonals downwards: k-th prime p such that cyclic digit shifts produce exactly n different primes.
2, 3, 13, 5, 17, 113, 7, 31, 131, 1193, 11, 37, 197, 1931, 11939, 19, 71, 199, 3119, 19391, 193939, 23, 73, 311, 3779, 19937, 199933, 17773937, 29, 79, 337, 7793, 37199, 319993, 39371777, 119139133, 41, 97, 373, 7937, 39119, 331999, 71777393, 133119139
Offset: 1
Examples
Array starts 2, 3, 5, 7, 11, 19, 23, ... 13, 17, 31, 37, 71, 73, 79, ... 113, 131, 197, 199, 311, 337, 373, ... 1193, 1931, 3119, 3779, 7793, 7937, 9311, ... 11939, 19391, 19937, 37199, 39119, 71993, 91193, ... 193939, 199933, 319993, 331999, 391939, 393919, 919393, ... 17773937, 39371777, 71777393, 73937177, 77393717, 77739371, 93717773, ... 119139133, 133119139, 139133119, 191391331, 311913913, 331191391, 913311913, ... ...
Links
- Robert G. Wilson v, Antidiagonals n = 1..13, flattened
Programs
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PARI
eva(n) = subst(Pol(n), x, 10) rot(n) = if(#Str(n)==1, v=vector(1), v=vector(#n-1)); for(i=2, #n, v[i-1]=n[i]); u=vector(#n); for(i=1, #n, u[i]=n[i]); v=concat(v, u[1]); v count_primes(n) = my(d=digits(n), i=0); while(1, if(ispseudoprime(eva(d)), i++); d=rot(d); if(d==digits(n), return(i))) row(n, terms) = my(i=0); forprime(p=1, , if(count_primes(p)==n, print1(p, ", "); i++); if(i==terms, print(""); break)) array(rows, cols) = for(x=1, rows, row(x, cols)) array(7, 7) \\ print initial 7 rows and 7 columns of array
Comments