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 A179631 Primes p such that p plus or minus the (sum of its digits and sum of squares of its digits) is a prime. 1
 23, 229, 239, 283, 359, 563, 599, 683, 809, 829, 853, 883, 1181, 1217, 1787, 1811, 1847, 2069, 2411, 2693, 2939, 3329, 3583, 4547, 4871, 4877, 5059, 5099, 5171, 5683, 5693, 5717, 6203, 6269, 6353, 6829, 7487, 7541, 8629, 8747, 9239, 9283, 10181 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Negative primes not permitted. - Harvey P. Dale, Sep 02 2015 LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 EXAMPLE a(3)=239 since 239+(2+3+9)+(2^2+3^2+9^2)=239+14+94=347 is prime AND 239-14-94=131 is prime. MATHEMATICA sdQ[n_]:=Module[{sd=Total[IntegerDigits[n]]+Total[IntegerDigits[n]^2]}, sd

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Last modified September 10 08:45 EDT 2024. Contains 375786 sequences. (Running on oeis4.)