A293041 a(n) is the least k such that [mu(k), mu(k+1), ..., mu(k+n-1)] forms a palindrome, where mu = A008683.

1, 2, 3, 62, 4, 61, 15, 115, 14, 116, 13, 831, 12, 37173, 597, 457472, 596, 2955661, 595, 6495574, 2456, 6495573, 41227, 4592266913, 66930, 52671417265, 66929, 52671417264, 66928

Offset

1,2

Comments

a(n+2) >= a(n) - 1.

a(n) exists: e.g. by the Chinese Remainder Theorem there are arbitrarily long intervals where mu = 0.

Links

Table of n, a(n) for n=1..29.

Mathematics StackExchange, Is there a Mobius palindrome?

Maple

mu:= proc(n) option remember; numtheory:-mobius(n) end proc:
ispali:= proc(L) andmap(i -> (L[i]=L[-i]), [$1..nops(L)/2]) end proc;
f:= proc(n) local k;
  for k from 1 do
    if ispali(map(mu, [$k..k+n-1])) then return k fi
  od;
end proc:
map(f, [$1..30]);

Crossrefs

Cf. A008683.

Sequence in context: A072875 A093551 A173915 * A284755 A061452 A369903

Adjacent sequences: A293038 A293039 A293040 * A293042 A293043 A293044

Keyword

nonn,more

Author

Robert Israel, Sep 28 2017

Extensions

a(24)-a(29) from Lukas Naatz, Jan 10 2020

Status

approved