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A276025
Next prime after concatenate of n, n times (A000461).
1
2, 23, 337, 4447, 55579, 666667, 7777801, 88888901, 1000000007, 10101010101010101073, 1111111111111111111189, 121212121212121212121327, 13131313131313131313131439, 1414141414141414141414141451, 151515151515151515151515151607, 16161616161616161616161616161709, 1717171717171717171717171717171741
OFFSET
1,1
LINKS
Dana Jacobsen, Table of n, a(n) for n = 1..332 (last entry has 996 digits)
Eric Weisstein's World of Mathematics, Next Prime.
FORMULA
a(n) = A007918(A000461(n)).
a(n) = A000040(A000720(A000461(n))+1).
EXAMPLE
a(5) = 55579, since this is the next prime after 55555.
MAPLE
a:= n-> nextprime(parse(cat(n$n))):
seq(a(n), n=1..20); # Alois P. Heinz, Aug 18 2016
MATHEMATICA
Table[NextPrime[n ((10^(n Floor[Log[10, 10 n]]) - 1)/(10^Floor[Log[10, 10 n]] - 1)), Plus[1]], {n, 1, 17}]
PROG
(PARI) a000461(n) = my(i=1, k=n); while(i < n, k=eval(Str(k, n)); i++); k
a(n) = nextprime(a000461(n)) \\ Felix Fröhlich, Aug 18 2016
(Perl) use ntheory ":all"; sub a276025 { my $n=shift; next_prime("$n" x $n); } Dana Jacobsen, Aug 22 2016
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Ilya Gutkovskiy, Aug 16 2016
STATUS
approved