OFFSET
1,3
LINKS
Michael De Vlieger, Table of n, a(n) for n = 1..10000
Michael De Vlieger, Raster showing a(n) > 0 in black else white, n = 1..10^6, in rows of 1000 pixels.
EXAMPLE
MATHEMATICA
c = 1; Reap[Do[Sow@ If[PrimeQ[10^(1 + Floor@ Log10[#]) - #], c++, -1] &[Prime[n]], {n, 73}]][[-1, -1]] (* or, generate nn <= 10^6 terms of this sequence from the bitmap: *)
Block[{nn = 10^4, s = Flatten@ ImageData[Import["https://oeis.org/A359122/a359122.png"]] /. {1. -> 0, 0. -> 1}, c}, c = 1; Map[If[# == 0, -1, c++] &, s[[1 ;; nn]]]] (* Michael De Vlieger, Dec 18 2022 *)
CROSSREFS
KEYWORD
sign
AUTHOR
N. J. A. Sloane, Dec 18 2022
STATUS
approved