A185714 -id:A185714 - cp's OEIS frontend

A185712 a(n) = number of primes <= n that end in 3.

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

Offset: 1

N. J. A. Sloane, Feb 10 2011

Partial sums of A185706.

G. C. Greubel, Table of n, a(n) for n = 1..5000
A. Granville and G. Martin, Prime number races, arXiv:math/0408319 [math.NT], 2004.
A. Granville and G. Martin, Prime number races, Amer. Math. Monthly, 113 (No. 1, 2006), 1-33.

Cf. A185705, A185706, A185708, A185709, A185711, A185712, A185714, A185715.

Accumulate[Table[If[PrimeQ[n] && Mod[n, 10] == 3, 1, 0], {n, 50}]] (* G. C. Greubel, Jul 10 2017 *)

A185715 a(n) = number of primes <= n that end in 9.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 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, 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, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6

Offset: 1

N. J. A. Sloane, Feb 10 2011

Partial sums of A185709.

G. C. Greubel, Table of n, a(n) for n = 1..5000
A. Granville and G. Martin, Prime number races, arXiv:math/0408319 [math.NT], 2004.
A. Granville and G. Martin, Prime number races, Amer. Math. Monthly, 113 (No. 1, 2006), 1-33.

Cf. A185705, A185706, A185708, A185709, A185711, A185712, A185714, A185715.

Accumulate[Table[If[PrimeQ[n] && Mod[n, 10] == 9, 1, 0], {n, 50}]] (* G. C. Greubel, Jul 10 2017 *)

a(n) = sum(k=1, n, if ((k % 10)==9, isprime(k))); \\ Michel Marcus, Jul 11 2017

A185711 a(n) = number of primes <= n that end in 1.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 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, 3, 3, 3, 3, 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, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6

Offset: 1

N. J. A. Sloane, Feb 10 2011

Partial sums of A185705.

G. C. Greubel, Table of n, a(n) for n = 1..5000
A. Granville and G. Martin, Prime number races, arXiv:math/0408319 [math.NT], 2004.
A. Granville and G. Martin, Prime number races, Amer. Math. Monthly, 113 (No. 1, 2006), 1-33.

Cf. A185705, A185706, A185708, A185709, A185711, A185712, A185714, A185715.

Accumulate[Table[If[PrimeQ[n]&&Mod[n,10]==1,1,0],{n,120}]] (* Harvey P. Dale, May 30 2016 *)

A300399 a(n) = number of primes that end in 7 among the first 10^n primes.

Original entry on oeis.org

2, 24, 254, 2508, 25015, 250014, 2500283, 25000402, 250002505, 2500005319, 25000014226, 250000051446

Offset: 1

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

			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 7.

Cf. A006988, A030432, A185714, A300397, A300398, A300400.

a(n) = #select(x->((x % 10) == 7), primes(10^n)); \\ Michel Marcus, Mar 07 2018

a(n) = A185714(A006988(n)). - Michel Marcus, Mar 20 2018

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

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A185712 a(n) = number of primes <= n that end in 3.

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A185715 a(n) = number of primes <= n that end in 9.

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A185711 a(n) = number of primes <= n that end in 1.

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A300399 a(n) = number of primes that end in 7 among the first 10^n primes.

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