A364271 Initial digit of n^((n + 1)^(n + 2)).

0, 1, 2, 3, 1, 7, 1, 7, 2, 8, 1, 1, 1, 2, 7, 1, 9, 1, 2, 2, 4, 5, 1, 7, 3, 2, 4, 1, 2, 6, 2, 1, 2, 2, 1, 8, 1, 6, 1, 5, 2, 8, 8, 3, 9, 3, 4, 2, 4, 3, 1, 6, 2, 1, 6, 6, 9, 1, 9, 2, 5, 2, 9, 9, 6, 8, 4, 2, 7, 7, 6, 1, 2, 2, 3, 1, 2, 6, 1, 1, 6, 1, 1, 2, 3, 5, 1

Offset: 0

Author

Marco Ripà, Oct 20 2023

Keywords

• nonn
• base

Examples

			a(2) = 2, since 2^((2 + 1)^(2 + 2)) = 2417851639229258349412352.
		

Links

• Kevin Ryde, C code using MPFR

Crossrefs

Cf. A000030, A030198, A365689 (final digit).

Programs

C

/* See links */

Mathematica

Join[{0}, Table[Floor[n^((n+1)^(n+2))/10^Floor[Log10[n^((n+1)^(n+2))]]], {n, 86}]]

Formula

a(n) = floor(t / 10^floor(log_10(t))) where t = n^((n + 1)^(n + 2)).

a(n) = A000030(A030198(n)).

Extensions

More terms from Kevin Ryde, Oct 27 2023