A119298 Total number of 7's digits in the first 10^n primes.

2, 34, 551, 6338, 72319, 809360, 9543704, 104376285, 1136782466, 12273965395, 134080968533, 1448607569210

Offset: 1

Author

Enoch Haga, May 13 2006

Keywords

• more
• nonn
• base

Examples

			At a(1)=2 there are 2 7's digits in the first 10^1 primes.
		

Crossrefs

Cf. A119290, A119291, A119292, A119293, A119294, A119295, A119296, A119297, A119299, A119300.

Programs

Maple

A119298 := proc(n) option remember: local k,s,lim: if(n=0)then return 0:fi: lim:=10^n: s:=procname(n-1): for k from 10^(n-1)+1 to lim do s:=s+nops([SearchAll("7",convert(ithprime(k),string))]): od: return s: end: seq(A119298(n),n=1..4); # Nathaniel Johnston, May 09 2011

Mathematica

Table[Count[IntegerDigits[Prime[Range[10^n]]], 7, 2], {n, 6}] (* Robert Price, May 02 2019 *)
Table[Total[Table[DigitCount[p,10,7],{p,Prime[Range[10^n]]}]],{n,7}] (* The program generates the first seven terms of the sequence. *) (* Harvey P. Dale, Dec 10 2024 *)

Extensions

Offset changed from 0 to 1 by Nathaniel Johnston, May 09 2011

a(8)-a(11) from Robert Price, Nov 05 2013

a(12) from Marek Hubal, Mar 04 2019