A116074 - OEIS

A116074

Primes that have the property that deleting some digit results in a prime with the same multiplicative order, or period (repeating length of 1/p).

2161, 155801, 263201, 445001, 617801, 755401, 758201, 1142201, 1273001, 1293401, 1352201, 1491001, 1494401, 1628801, 1801601, 2414201, 2447801, 2611001, 2629001, 2876801, 3049801, 3267001, 3422801, 3541801, 3744401, 3759001, 3825401, 3838201, 3871601, 3952601

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..30.

C. K. Caldwell, Prime Curios

EXAMPLE

2161 and 211 (delete a digit from 2161) are both primes with period 30, so 2161 is in the sequence.

MATHEMATICA

pL[n_] := MultiplicativeOrder[10, n]; hQ[n_] := Block[{s, d = IntegerDigits@n, pe}, s = Union@ Select[FromDigits /@ (Delete[d, #] & /@ Range@ Length@d), PrimeQ]; If[s != {}, pe = pL@n; s = Select[s, pe == pL@# &]]; s != {}]; Select[

Prime@ Range[10^5], hQ] (* Giovanni Resta, Jan 06 2014 *)

CROSSREFS

Cf. A116075, A116076.

Sequence in context: A061335 A159238 A289725 * A252563 A035872 A126831

Adjacent sequences: A116071 A116072 A116073 * A116075 A116076 A116077

KEYWORD

base,nonn

AUTHOR

G. L. Honaker and Jud McCranie, Feb 03 2006

EXTENSIONS

a(5)-a(30) from Giovanni Resta, Jan 06 2014

STATUS

approved