

A300400


a(n) = number of primes that end in 9 among the first 10^n primes.


3



2, 24, 246, 2491, 25009, 249940, 2499751, 25000026, 249997694, 2499999305, 24999974939, 249999962302
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..12.
Caldwell and Honaker, Prime Curios!


FORMULA

a(n) = A185715(A006988(n)).  Michel Marcus, Mar 20 2018


EXAMPLE

a(1) = 2 because the first 10 primes are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, among which there are two primes ending in 9.


PROG

(PARI) a(n) = #select(x>((x % 10) == 9), primes(10^n)); \\ Michel Marcus, Mar 07 2018


CROSSREFS

Cf. A006988, A030433, A185715, A300397, A300398, A300399.
Sequence in context: A132596 A099669 A019520 * A187584 A173228 A061190
Adjacent sequences: A300397 A300398 A300399 * A300401 A300402 A300403


KEYWORD

nonn,base,more


AUTHOR

G. L. Honaker, Jr., Mar 05 2018


EXTENSIONS

a(3)a(8) from Chuck Gaydos
a(9) from Jon E. Schoenfield, Mar 20 2018
a(10)a(12) from Giovanni Resta, Mar 27 2018


STATUS

approved



