A077651 Initial digit of phi(n), where phi is Euler totient function, A000010.

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

Offset

1,3

Links

Antti Karttunen, Table of n, a(n) for n = 1..10000

Formula

a(n) = A000030(A000010(n)).

Mathematica

Table[First[IntegerDigits[EulerPhi[w]]], {w, 1, 128}]

Prog

(PARI) A077651(n) = (digits(eulerphi(n))[1]); \\ Antti Karttunen, Dec 04 2017

Crossrefs

Cf. A000030, A000010, A004085.

Sequence in context: A278229 A233027 A262550 * A004085 A293482 A086296

Adjacent sequences: A077648 A077649 A077650 * A077652 A077653 A077654

Keyword

base,nonn

Author

Labos Elemer, Nov 19 2002

Status

approved