A363093 Leading digit of 7^n.

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

Offset

0,2

Links

Table of n, a(n) for n=0..100.

Formula

a(n) = A000030(A000420(n)).

Mathematica

a[n_] := IntegerDigits[7^n][[1]]; Array[a, 100, 0] (* Amiram Eldar, Jul 15 2023 *)

Prog

(PARI) a(n) = digits(7^n)[1];

Crossrefs

Cf. A008952, A060956, A111395, A362871, A363249, A364185.

Cf. A000030, A000420, A001903, A008568.

Sequence in context: A200121 A198348 A019857 * A296474 A194705 A344906

Adjacent sequences: A363090 A363091 A363092 * A363094 A363095 A363096

Keyword

nonn,base,easy

Author

Seiichi Manyama, Jul 15 2023

Status

approved