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 A103665 Primes p such that the number of divisors of p-1 is greater than the number of divisors of p+1. 7
 13, 31, 37, 43, 61, 67, 73, 97, 101, 109, 113, 127, 151, 157, 163, 181, 193, 211, 229, 241, 257, 271, 277, 281, 283, 313, 331, 337, 353, 373, 379, 397, 401, 409, 421, 433, 457, 463, 487, 521, 523, 541, 547, 571, 577, 601, 613, 617, 631, 641, 661, 673, 677 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Mathematica coding by Wouter Meeussen and Robert G. Wilson v. LINKS Hugo Pfoertner, Table of n, a(n) for n = 1..10000 EXAMPLE a(1)=13 because d(12)=6 > d(14)=4. MATHEMATICA Select[Prime[Range[2, 140]], Length[Divisors[ # - 1]] > Length[Divisors[ # + 1]] &] PROG (PARI) forprime (k=2, 700, if(numdiv(k-1)>numdiv(k+1), print1(k, ", "))) \\ Hugo Pfoertner, Nov 30 2017 CROSSREFS Cf. A008328 number of divisors of p-1, A008329 number of divisors of p+1, A103664, A103666, A103667. Sequence in context: A046414 A023694 A038465 * A040050 A040086 A176181 Adjacent sequences:  A103662 A103663 A103664 * A103666 A103667 A103668 KEYWORD nonn AUTHOR Hugo Pfoertner, Feb 19 2005 STATUS approved

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Last modified August 3 05:37 EDT 2020. Contains 336197 sequences. (Running on oeis4.)