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A093339 Middle digits of primes with an odd number of digits. 3
2, 3, 5, 7, 0, 0, 0, 0, 1, 2, 3, 3, 3, 4, 5, 5, 6, 6, 7, 7, 8, 9, 9, 9, 9, 1, 2, 2, 2, 3, 3, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 0, 1, 1, 1, 3, 3, 4, 4, 5, 5, 6, 7, 7, 8, 8, 9, 0, 0, 1, 2, 3, 3, 3, 4, 4, 5, 6, 6, 6, 7, 8, 9, 9, 0, 0, 2, 2, 4, 4, 5, 6, 6, 7, 7, 8, 9, 9, 0, 0, 1, 1, 1, 3, 4, 4, 4, 5, 5, 6, 7, 7, 8, 9, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 2..1000

MATHEMATICA

mdp[n_]:=Module[{idn=IntegerDigits[n], len=IntegerLength[n]}, If[EvenQ[len], -1, idn[[(len-1)/2+1]]]]; Select[mdp/@Prime[Range[500]], NonNegative] (* Harvey P. Dale, Feb 26 2012 *)

PROG

(PARI) midd(n) = { forprime(x=2, n, s = Str(x); ln = length(s); if(ln<2, p=1, p = (ln-1)/2+1); if(ln%2, md = eval(mid(s, p, 1)); print1(md", ") ) ) } \ Get a substring of length n from string str starting at position s in str. mid(str, s, n) = { v =""; tmp = Vec(str); ln=length(tmp); for(x=s, s+n-1, v=concat(v, tmp[x]); ); return(v) }

CROSSREFS

Cf. A077648, A007652.

Sequence in context: A261579 A270517 A124648 * A113566 A020775 A041000

Adjacent sequences:  A093336 A093337 A093338 * A093340 A093341 A093342

KEYWORD

base,nonn

AUTHOR

Cino Hilliard, Apr 25 2004

STATUS

approved

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Last modified May 18 09:14 EDT 2021. Contains 343995 sequences. (Running on oeis4.)