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A180560 The number of times the n-th prime, p, can become a different prime under any mapping of some single decimal digit <=> with some other single decimal digit. 45
3, 3, 3, 3, 0, 9, 8, 6, 7, 5, 5, 7, 5, 8, 7, 7, 5, 4, 6, 6, 9, 7, 7, 5, 6, 4, 7, 12, 10, 6, 6, 5, 10, 9, 6, 6, 9, 9, 12, 7, 10, 6, 6, 7, 9, 3, 6, 7, 7, 3, 4, 6, 8, 6, 4, 7, 4, 6, 6, 5, 7, 5, 8, 4, 5, 7, 5, 7, 10, 6, 5, 7, 8, 3, 8, 5, 6, 8, 8, 8, 8, 7, 7, 3, 9, 6, 2, 6, 9, 7, 9, 6, 3, 7, 3, 6, 7, 6, 6, 7, 5, 9, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

First occurrence of k, from 0 to 45: 5, 195, 87, 1, 18, 10, 8, 9, 7, 6, 29, 172, 28, 1275, 7666, 1279, ..., .

LINKS

Table of n, a(n) for n=1..103.

Index to Primes, Primes that become a different prime under some mapping.

EXAMPLE

2 can become either 3, 5 or 7 under the proper mapping, therefore a(1)=3. 11 cannot become any other prime regardless of the mapping, therefore a(5)=0.

MATHEMATICA

fQ[n_] := Block[{id = IntegerDigits@n}, (MemberQ[id, s[[1]]] || MemberQ[id, s[[2]]]) && PrimeQ[ FromDigits[id /. {s[[1]] -> s[[2]], s[[2]] -> s[[1]] }] ]]; t = Sort@ Flatten@ Table[s = {j, k}; Select[ Prime@ Range@ 100, fQ], {j, 0, 8}, {k, j + 1, 9}]; Table[ Length@ Position[t, Prime@ n], {n, 100}]

CROSSREFS

Cf. A175791, A180517 thru A180559, A175789, A180561.

Sequence in context: A300372 A132973 A107760 * A320085 A172368 A138070

Adjacent sequences:  A180557 A180558 A180559 * A180561 A180562 A180563

KEYWORD

base,nonn

AUTHOR

Zak Seidov and Robert G. Wilson v, Sep 09 2010

STATUS

approved

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Last modified October 18 02:23 EDT 2019. Contains 328135 sequences. (Running on oeis4.)