The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation. Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”). Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A096469 Smallest number m such that the concatenation of n+1 numbers m^0, m^1,..., m^(n-1), m^n is a prime. 0
 1, 3, 33, 23, 237, 93, 37, 291, 421, 7, 471, 213, 1941, 29, 43, 17, 327, 1, 523, 21, 3403, 1, 13281, 3851, 3583, 3081, 1681, 157, 34989, 5411, 2431, 1229, 4767, 1021, 8397, 603, 429, 561, 6571, 47, 8601, 347, 15027, 687, 1611, 273, 29979, 201, 5719 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Conjecture: This sequence is infinite. a(n) = 1 if and only if n + 1 is in the sequence A004023, so a(1) = a(18) = a(22) = a(316) = a(1030) = a(49080) = a(86452) = 1 and there are no other n less than 86453 such that a(n) = 1. Every term of this sequence is odd and for each n, 5 doesn't divide a(n). a(50) is greater than 11111. LINKS EXAMPLE a(2) = 3 because 3^0 = 1, 3^1 = 3, and 3^2 = 9; 139 is prime and 3 is the smallest number that gives this result. a(3) = 33 because 33^0 = 1; 33^1 = 33; 33^2 = 1089; 33^3 = 35937; 133108935937 is a prime and 33 is the smallest number that gives this result. MATHEMATICA snm[n_]:=Module[{m=1}, While[!PrimeQ[FromDigits[Flatten[ IntegerDigits/@ (m^Range[0, n])]]], m++]; m]; Array[snm, 50] (* Harvey P. Dale, Aug 10 2016 *) CROSSREFS Cf. A004023, A213072. Sequence in context: A203323 A222683 A134474 * A106423 A077328 A106413 Adjacent sequences:  A096466 A096467 A096468 * A096470 A096471 A096472 KEYWORD base,nonn AUTHOR Farideh Firoozbakht, Jun 23 2004 EXTENSIONS First example corrected by Harvey P. Dale, Aug 10 2016 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 4 17:50 EST 2021. Contains 349526 sequences. (Running on oeis4.)