login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A097468 Number of 1's in the decimal expansion of the lesser of twin primes. 0
0, 0, 2, 1, 0, 1, 0, 1, 2, 1, 1, 1, 1, 2, 1, 0, 0, 0, 1, 2, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 2, 2, 1, 2, 2, 3, 1, 1, 1, 2, 2, 1, 2, 2, 1, 1, 2, 1, 1, 2, 1, 2, 1, 2, 1, 1, 0, 1, 0, 3, 1, 2, 0, 0, 0, 0, 1, 0, 1, 0, 0, 2, 0, 0, 1, 0, 0, 2, 1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,3

COMMENTS

n=5000,d=1 in PARI code below.

LINKS

Table of n, a(n) for n=2..106.

EXAMPLE

11 is the third lesser twin prime so 2 is the third entry

MATHEMATICA

DigitCount[#, 10, 1]&/@(Select[Partition[Prime[Range[1000]], 2, 1], #[[2]] - #[[1]] == 2&][[All, 1]]) (* Harvey P. Dale, Dec 24 2018 *)

PROG

(PARI) g(n, d) = forprime(x=1, n, if(isprime(x+2), print1(countchr(x, d)", "))) \Count the occurrences of char in string str countchr(str, char) = { local(ln, x, c); str=Str(str); \This allows leaving quotes off input char=Str(char); c=0; ln=length(str); for(x=1, ln, if(mid(str, x, 1)==char, c++); ); return(c) } \ Get a substring of length n from string str starting at position s in str. mid(str, s, n) = { local(v, ln, x, tmp); v =""; tmp = Vec(str); ln=length(tmp); for(x=s, s+n-1, v=concat(v, tmp[x]); ); return(v) }

CROSSREFS

Sequence in context: A271420 A099313 A316491 * A339975 A283144 A098381

Adjacent sequences:  A097465 A097466 A097467 * A097469 A097470 A097471

KEYWORD

base,nonn

AUTHOR

Cino Hilliard, Aug 23 2004

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 18 14:29 EDT 2021. Contains 345114 sequences. (Running on oeis4.)