A075522 Number of steps to reach the first nonprime (=A075523(n)) starting with the n-th prime p and iterating the map k -> 4*k+(p mod 4), or -1 if no integer is ever reached.

1, 1, 1, 3, 3, 2, 1, 2, 1, 1, 2, 2, 1, 1, 2, 1, 2, 1, 3, 1, 2, 1, 1, 1, 2, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 4, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 1, 2, 2, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 3, 1, 1, 1, 1, 1, 3, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 4

Offset

1,4

Comments

a(A075521(n)) > 1;

a(n) = a(A075520(n))+1 for n with A075520(n) prime.

Links

Table of n, a(n) for n=1..105.

Example

A000040(4)=7 and (7 mod 4) = 3: 7 -> 4*7+3=31 -> 4*31+3=127 -> 4*127+3=511 = A075523(4), therefore a(4)=3.

Crossrefs

Cf. A075520, A075519.

Sequence in context: A060574 A283987 A286443 * A186144 A090544 A283755

Adjacent sequences: A075519 A075520 A075521 * A075523 A075524 A075525

Keyword

nonn

Author

Reinhard Zumkeller, Sep 19 2002

Status

approved