A097468 Number of 1's in the decimal expansion of the lesser of twin primes.

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

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