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A198190
Primes from the decimal expansion of sqrt(2), sorted first by the final digit index and then by length.
0
41, 2, 421, 3, 13, 5, 2, 3, 23, 5623, 135623, 42135623, 4142135623, 7, 37, 56237, 3, 73, 373, 3562373, 213562373, 7309, 37309, 5, 5048801, 414213562373095048801, 7, 887, 488016887, 142135623730950488016887, 2, 2, 688724209, 414213562373095048801688724209
OFFSET
1,1
EXAMPLE
The first digit, 1, is not prime.
The second digit, 4, cannot terminate any prime.
The third digit, 1, is not prime, but 41 is, so a(1) = 41. 141 is not prime, so it is not in the sequence.
PROG
(PARI) v=[1, 4, 1, 4, 2, 1, 3, 5, 6, 2, 3, 7, 3, 0, 9, 5, 0, 4, 8, 8, 0, 1, 6, 8, 8, 7, 2, 4, 2, 0, 9, 6, 9]
for(n=1, #v, x=0; p=1; forstep(k=n, 1, -1, x+=p*v[k]; p*=10; if(v[k]&&isprime(x), print1(x", "))))
CROSSREFS
Cf. A002193.
Sequence in context: A283895 A051317 A036189 * A106424 A126636 A095188
KEYWORD
nonn,base
AUTHOR
STATUS
approved