A276694 Where records occur in A209252.

0, 11, 13, 101, 107, 177, 357, 1001, 1011, 10759, 11487, 42189, 113183, 344253, 1851759, 4787769, 15848679, 139367847, 240889077

Offset

1,2

Comments

Except for the first term, all terms are coprime to 10. - Chai Wah Wu, Sep 19 2016

Links

Table of n, a(n) for n=1..19.

Maple

with(numtheory): P:= proc(q) local d, j, k, n, t, x; x:=4; print(0);
for n from 1 to q do d:=ilog10(n)+1; t:=0;
for k from 0 to d-1 do for j from 0 to 9 do
if isprime(trunc(n/10^(k+1))*10^(k+1)+j*10^k+(n mod 10^k))
then t:=t+1; fi; od; od;
if isprime(n) then if t-d>x then x:=t-d; print(n); fi; else
if t>x then x:=t; print(n); fi; fi; od; end: P(10^9);

Crossrefs

Cf. A000040, A209252.

Sequence in context: A056436 A334930 A089824 * A086549 A108090 A136296

Adjacent sequences: A276691 A276692 A276693 * A276695 A276696 A276697

Keyword

nonn,base,more

Author

Paolo P. Lava, Sep 14 2016

Extensions

a(18)-a(19) from Chai Wah Wu, Sep 19 2016

Status

approved