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A050814 Inserting any even or any odd digit between adjacent digits of prime p produces distinct prime and composite numbers. 0
5333, 1454969, 1466833, 1790531, 1794343, 1883113, 1984459, 2179993, 2410523, 2567891, 3100301, 3259567, 3424783, 3700153, 3954131, 3972979, 4046671, 4134133, 4280033, 4544641, 4691851, 4692641, 4848523, 5006831, 5118307 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..25.

EXAMPLE

5333 produces five primes when an even digit is inserted (5030303, 5232323, 5434343, 5636363, 5838383) and five composites when an odd digit is inserted (5131313, 5333333, 5535353, 5737373, 5939393).

MATHEMATICA

a[n_, k_]:=Union[Boole/@PrimeQ[Table[FromDigits[Riffle[IntegerDigits[n], i]], {i, k+2*Range[0, 4]}]]]; t={}; Do[p=Prime[i]; x=a[p, 1]; y=a[p, 0]; If[x=={0}&&y=={1}||x=={1}&&y=={0}, AppendTo[t, p]], {i, 100, 190000}]; t (* Jayanta Basu, Jun 01 2013 *)

CROSSREFS

Cf. A050674-A050719.

Sequence in context: A031571 A031751 A023342 * A234213 A187435 A023939

Adjacent sequences:  A050811 A050812 A050813 * A050815 A050816 A050817

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, Oct 15 1999

EXTENSIONS

Offset changed to 1 by Jon E. Schoenfield, Oct 17 2019

STATUS

approved

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Last modified June 13 10:36 EDT 2021. Contains 344988 sequences. (Running on oeis4.)