A229181 Number of decimal digits in the variant of A047777(n) (decimal expansion of Pi cut in "prime chunks") without the restriction that all primes must be different.

1, 5, 1, 3, 1, 2, 1, 4, 3057, 1, 1, 3, 1, 1, 748, 2, 2, 1, 2, 83, 5, 1, 2, 71, 10, 1, 1, 2, 2, 2, 1, 1, 3, 1, 14, 2, 5, 51, 1, 6, 1, 6, 3, 2, 9, 1, 16, 2, 3, 43, 1, 6, 19, 1, 5, 3, 1999, 1, 1, 2, 22, 1, 3, 1, 2, 2, 1, 2, 2, 5, 1, 1, 1, 1, 4, 1, 1, 3, 7, 5, 1, 6, 4, 3, 1, 10, 7, 1, 2, 11, 2, 5, 1, 13, 1, 20, 16, 1, 9, 16

Offset

1,2

Comments

A variant of A121267. First differences of A053013. See these two sequences for further details.

Links

Table of n, a(n) for n=1..100.

C. Rivera, Prime strings

Mathematica

A229181 = {1}; digits = Join[{{1}}, RealDigits[Pi, 10, 10^4] // First // Rest]; digits //. {a:({_Integer..}..), b__Integer /; PrimeQ[FromDigits[{b}]], c___Integer} :> (Print[lg = {b} // Length]; AppendTo[A229181, lg]; {{1}, c}) ; A229181 (* Jean-François Alcover, Oct 17 2013 *)

Prog

(PARI) default(realprecision, 5000); c=Pi/10; u=[]; for(k=1, 9e9, ispseudoprime(c\.1^k) & !print1(k, ", ") & k=0*c=frac(c*10^k))

Crossrefs

Cf. A047777, A053013, A121267, A229155.

Sequence in context: A254378 A134568 A198798 * A121267 A111740 A327921

Adjacent sequences: A229178 A229179 A229180 * A229182 A229183 A229184

Keyword

nonn,base

Author

M. F. Hasler, Sep 15 2013

Extensions

More terms from Jean-François Alcover, Oct 17 2013

Status

approved