A073505
Number of primes == 1 (mod 10) less than 10^n.
Original entry on oeis.org
0, 5, 40, 306, 2387, 19617, 166104, 1440298, 12711386, 113761519, 1029517130, 9401960980, 86516370000
Offset: 1
a(2) = 5 because there are 5 primes == 1 (mod 10) less than 10^2. They are 11, 31, 41, 61 and 71.
Cf.
A006880,
A087630,
A073506,
A073507,
A073508,
A073509,
A073510,
A073511,
A073512,
A073513,
A073514,
A073515,
A073516,
A073517.
-
c = 0; k = 1; Do[While[k < 10^n, If[PrimeQ[k], c++ ]; k += 10]; Print[c], {n, 1, 10}]
A073506
Number of primes == 3 (mod 10) less than 10^n.
Original entry on oeis.org
1, 7, 42, 310, 2402, 19665, 166230, 1440474, 12712499, 113765625, 1029509448, 9401979904, 86516427946
Offset: 1
a(2)=7 because there are 7 primes == 3 (mod 10) less than 10^2. They are 3, 13, 23, 43, 53, 73 and 83.
Cf.
A006880,
A087631,
A073505,
A073507,
A073508,
A073509,
A073510,
A073511,
A073512,
A073513,
A073514,
A073515,
A073516,
A073517.
-
c = 0; k = 3; Do[While[k < 10^n, If[PrimeQ[k], c++ ]; k += 10]; Print[c], {n, 1, 10}]
A073507
Number of primes == 7 (mod 10) less than 10^n.
Original entry on oeis.org
1, 6, 46, 308, 2411, 19621, 166211, 1440495, 12712314, 113764039, 1029518337, 9401997000, 86516367790
Offset: 1
a(2)=6 because there are 6 primes == 7 (mod 10) less than 10^2. They are 7, 17, 37, 47, 67 and 97.
Cf.
A006880,
A087632,
A073505,
A073506,
A073508,
A073509,
A073510,
A073511,
A073512,
A073513,
A073514,
A073515,
A073516,
A073517.
-
c = 0; k = 7; Do[While[k < 10^n, If[PrimeQ[k], c++ ]; k += 10]; Print[c], {n, 1, 10}]
A073508
Number of primes == 9 (mod 10) less than 10^n.
Original entry on oeis.org
0, 5, 38, 303, 2390, 19593, 166032, 1440186, 12711333, 113761326, 1029509896, 9401974132, 86516371101
Offset: 1
a(2) = 5 because there are 5 primes == 9 (mod 10) less than 10^2. They are 19, 29, 59, 79 and 89.
Cf.
A006880,
A087633,
A073505,
A073506,
A073507,
A073509,
A073510,
A073511,
A073512,
A073513,
A073514,
A073515,
A073516,
A073517.
-
c = 0; k = 9; Do[While[k < 10^n, If[PrimeQ[k], c++ ]; k += 10]; Print[c], {n, 1, 10}]
Showing 1-4 of 4 results.
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