A342962 a(n) is the least prime that starts a string of exactly n distinct primes p_1, p_2, ..., p_n where p_{i+1} = p_i+A085563(p_i), but p_n+A085563(p_n) is either not prime or equal to p_n.

2, 29, 229, 5639, 35969, 54191353

Offset

1,1

Comments

No further terms up to 10^9.

Links

Table of n, a(n) for n=1..6.

Example

a(3) = 229 because 229, 229+A085563(229) = 233, and 233+A085563(233) = 241 are prime but 241+A085563(241) = 243 is not.

Maple

f:= n -> n + convert(select(isprime, convert(n, base, 10)), `+`):
F:= proc(n) option remember; local t, x;
    x:= f(n);
  if x = n or not isprime(x) then 1 else 1+procname(x) fi
end proc:
V:= Vector(6): count:= 0: p:= 1:
while count < 6 do
  p:= nextprime(p); v:= F(p);
  if v <= 6 and V[v] = 0 then V[v]:= p; count:= count+1 fi
od:
convert(V, list);

Crossrefs

Cf. A085563, A342961.

Sequence in context: A020460 A178000 A036939 * A342971 A124301 A276196

Adjacent sequences: A342959 A342960 A342961 * A342963 A342964 A342965

Keyword

nonn,base,more

Author

J. M. Bergot and Robert Israel, Mar 31 2021

Status

approved