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A077648 Initial digits of prime numbers. 12
2, 3, 5, 7, 1, 1, 1, 1, 2, 2, 3, 3, 4, 4, 4, 5, 5, 6, 6, 7, 7, 7, 8, 8, 9, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A000030(A000040(n)).

MATHEMATICA

Table[First[IntegerDigits[Prime[n]]], {n, 1, 120}]

PROG

(MAGMA) [Intseq(p)[#Intseq(p)]: p in PrimesUpTo(600)]; // Bruno Berselli, Feb 14 2013

(PARI) a(n) = digits(prime(n))[1]; \\ Michel Marcus, Feb 11 2017

CROSSREFS

Cf. A000030, A000040.

Sequence in context: A230200 A113493 A060420 * A033308 A134690 A295868

Adjacent sequences:  A077645 A077646 A077647 * A077649 A077650 A077651

KEYWORD

base,nonn

AUTHOR

Labos Elemer, Nov 19 2002

STATUS

approved

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Last modified August 23 14:04 EDT 2019. Contains 326230 sequences. (Running on oeis4.)