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A077345
a(n) is the n-th prime whose decimal expansion begins with the decimal expansion of n.
4
11, 23, 37, 401, 509, 617, 719, 829, 953, 1033, 1171, 1279, 1373, 1483, 15013, 1697, 17021, 18049, 19001, 20051, 21067, 22031, 23027, 24097, 25127, 26107, 27103, 28123, 29153, 30161, 31159, 32189, 33161, 34259, 35171, 36241, 37243, 38299, 39241, 40237, 41263
OFFSET
1,1
COMMENTS
Original name was: Final terms of rows in A077344.
Subsidiary sequence: There can be a rearrangement of primes in groups so that the n-th group contains n primes beginning with n and not occurring earlier. E.g. the initial term of row 11 would be 113 and not 11.
MAPLE
u:= (h, t)-> select(isprime, [seq(h*10^t+k, k=0..10^t-1)]):
A:= proc(n, k) local l, p;
l:= proc() [] end; p:= proc() -1 end;
while nops(l(k))<n do p(k):= p(k)+1;
l(k):= [l(k)[], u(k, p(k))[]]
od: l(k)[n]
end:
a:= n-> A(n$2):
seq(a(n), n=1..45); # Alois P. Heinz, Sep 30 2015
MATHEMATICA
u[h_, t_] := Select[Table[h*10^t + k, {k, 0, 10^t - 1}], PrimeQ];
A[n_, k_] := Module[{l, p}, l[_] = {}; p[_] = -1; While[Length[l[k]] < n, p[k] = p[k] + 1; l[k] = Join[l[k], u[k, p[k]]]]; l[k][[n]]];
a[n_] := A[n, n];
Table[a[n], {n, 1, 45}] (* Jean-François Alcover, Oct 25 2021, after Alois P. Heinz *)
CROSSREFS
Cf. A077344.
Main diagonal of A262369.
Sequence in context: A275591 A250665 A339080 * A130282 A019356 A046440
KEYWORD
base,easy,nonn
AUTHOR
Amarnath Murthy, Nov 05 2002
EXTENSIONS
More terms and new name from Alois P. Heinz, Sep 30 2015
STATUS
approved