A089943 Number of digits in candidates Sierpiński numbers of the first kind.

1, 3, 20, 617, 315653, 41373247568, 355393490465494856466, 13111705528158638560001549984013213785610, 8923364382984350190045623219438187007104891998452120469899352728663188707599765

Offset

0,2

Links

Table of n, a(n) for n=0..8.

Eric Weisstein's World of Mathematics, Sierpiński Number of the First Kind

Formula

a(n) = ceiling(2^(n+2^n)*log_10(2)).

Mathematica

a[k_] := Ceiling[2^(k+2^k) Log[2]/Log[10]];

Crossrefs

Sequence in context: A203228 A174972 A300917 * A108699 A162134 A296408

Adjacent sequences: A089940 A089941 A089942 * A089944 A089945 A089946

Keyword

nonn,base

Author

Eric W. Weisstein, Nov 16 2003

Status

approved