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 A090194 Primes which when multiplied by their largest digit and 1 is added form another prime. 0
 2, 43, 61, 263, 433, 461, 601, 641, 653, 661, 821, 857, 1061, 1063, 1187, 1361, 1423, 1487, 1613, 1811, 1871, 1877, 2063, 2081, 2143, 2161, 2621, 2801, 2837, 3061, 3163, 3581, 3623, 3631, 3643, 3851, 4561, 5087, 5261, 5381, 5623, 5807, 5861, 6011, 6053 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..45. FORMULA In the prime sequence, select largest digit in each prime, multiply by the prime containing that digit, then add 1. If the result is another prime, add to sequence. EXAMPLE a(2)=43. Largest digit is 4. Multiply 43*4=172. 172+1=173, prime. PROG (PARI) isok(p) = isprime(p) && isprime(p*vecmax(digits(p))+1); \\ Michel Marcus, Jun 08 2014 CROSSREFS Cf. A060418. Sequence in context: A354726 A235473 A137415 * A107200 A079823 A107156 Adjacent sequences: A090191 A090192 A090193 * A090195 A090196 A090197 KEYWORD easy,nonn,base AUTHOR Enoch Haga, Jan 22 2004 STATUS approved

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Last modified February 29 10:33 EST 2024. Contains 370418 sequences. (Running on oeis4.)