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 A242092 Numbers n such that n and the digital reversal of the n-th prime in base 10 have the same distinct prime factors. 1
 86, 1357, 24146, 1028736826, 33667786628, 2132089369082 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS First 3 terms are all products of 2 primes. a(4) > 10^8. - Chai Wah Wu, Aug 15 2014 a(7) > 10^13. - Giovanni Resta, Dec 09 2019 LINKS EXAMPLE 86 = 2^1*43^1, the 86th prime is 443 and 344 = 2^3*43^1. 1357 = 59^1*23^1, the 1357th prime is 11213 and 31211 = 59^1*23^2. PROG (Python) from sympy import primefactors, prime A242092 = [n for n in range(1, 10**7) if primefactors(n) == primefactors(int(str(prime(n))[::-1]))] (PARI) rev(n)=r=""; d=digits(n); for(i=1, #d, r=concat(Str(d[i]), r)); eval(r) for(n=1, 10^7, p=rev(prime(n)); if(omega(n)==omega(p), if(gcd(n, p)==min(n, p), print1(n, ", ")))) \\ Derek Orr, Aug 14 2014 CROSSREFS Cf. A110751. Sequence in context: A034277 A254702 A206615 * A232859 A224259 A223915 Adjacent sequences:  A242089 A242090 A242091 * A242093 A242094 A242095 KEYWORD nonn,base,more,hard AUTHOR Chai Wah Wu, Aug 14 2014 EXTENSIONS a(4)-a(6) from Giovanni Resta, Dec 09 2019 STATUS approved

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Last modified August 10 20:21 EDT 2022. Contains 356039 sequences. (Running on oeis4.)