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A032437 Substrings from the right are prime numbers (using only odd digits different from 5). 12
3, 7, 13, 17, 37, 73, 97, 113, 137, 173, 197, 313, 317, 337, 373, 397, 773, 797, 937, 997, 1373, 1997, 3137, 3313, 3373, 3797, 7937, 9137, 9173, 9337, 9397, 13313, 33797, 39397, 79337, 79397, 91373, 91997, 99137, 99173, 99397, 139397, 379397 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

T. D. Noe, Table of n, a(n) for n = 1..58 [The complete list of terms]

C. Rivera, Prime strings

Eric Weisstein's World of Mathematics, Truncatable Prime.

MATHEMATICA

srpnQ[n_]:=AllTrue[FromDigits/@Table[Take[IntegerDigits[n], -i], {i, [n]}], PrimeQ]; Flatten[Table[Select[FromDigits/@ Tuples[{1, 3, 7, 9}, k], srpnQ], {k, 9}]] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jan 09 2015 *)

PROG

(PARI) is(n)=my(d=digits(n)); for(i=1, n, if(!isprime(fromdigits(d[i..n])), return(0))); 1 \\ Charles R Greathouse IV, Jun 25 2017

CROSSREFS

Cf. A033664, A024785, A020994, A024770, A052023, A052024, A052025, A050986, A050987.

Sequence in context: A113003 A045423 A214782 * A076746 A243706 A214696

Adjacent sequences:  A032434 A032435 A032436 * A032438 A032439 A032440

KEYWORD

nonn,fini,full,base,nice

AUTHOR

Carlos Rivera

EXTENSIONS

Single-digit terms added by Eric W. Weisstein.

STATUS

approved

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Last modified September 24 04:27 EDT 2017. Contains 292403 sequences.