A091098 - OEIS

A091098

Number of primes of the form 4k+1 less than 10^n.

1, 11, 80, 609, 4783, 39175, 332180, 2880504, 25423491, 227523275, 2059020280, 18803924340, 173032709183, 1602470783672, 14922284735484, 139619168787795, 1311778575685086, 12369977142579584, 117028833597800689, 1110409801150582707

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..20.

Marc Deléglise, Pierre Dusart, and Xavier-Francois Roblot, Counting primes in residue classes, Math. Comp. 73 (2004), no. 247, 1565-1575

Daniel Pareja, Prime Number Races

Eric Weisstein's World of Mathematics, Modular Prime Counting Function

MATHEMATICA

cnt=0; k=0; Table[lim=10^n; While[4k+1<lim, If[ PrimeQ[4k+1], cnt++ ]; k++ ]; cnt, {n, 6}]

CROSSREFS

Cf. A091099 (number of primes of the form 4k+3 less than 10^n).

Sequence in context: A021024 A127021 A326243 * A091115 A024146 A233176

Adjacent sequences: A091095 A091096 A091097 * A091099 A091100 A091101

KEYWORD

nonn,changed

AUTHOR

T. D. Noe, Dec 19 2003

EXTENSIONS

a(10)-a(16) from Robert G. Wilson v, Dec 22 2003

a(17)-a(20) from Marc Deleglise, Jun 28 2007

STATUS

approved