A121519 -id:A121519 - cp's OEIS frontend

A103203 Primes which have more primitive roots than any smaller prime.

2, 5, 11, 17, 23, 29, 41, 47, 53, 59, 83, 107, 137, 149, 167, 173, 179, 227, 257, 263, 269, 293, 317, 347, 359, 383, 389, 467, 479, 503, 509, 557, 563, 587, 653, 719, 773, 797, 809, 839, 857, 863, 887, 929, 977, 983, 1019, 1049, 1097, 1109, 1187, 1229

Offset: 1

Don Reble, Mar 19 2005

nonn

Jeppe Stig Nielsen, Table of n, a(n) for n = 1..100000

Cf. A103521, A121519, A008330.

my(record=0, r); forprime(p=2, 1500, r=eulerphi(p-1); if(r>record, record=r; print1(p,", "))) \\ Jeppe Stig Nielsen, Oct 18 2019

A306371 Number of primitive roots of prime A103521(n).

Original entry on oeis.org

1, 2, 4, 6, 8, 12, 16, 20, 24, 32, 36, 40, 48, 64, 72, 80, 96, 120, 144, 160, 176, 200, 216, 240, 288, 320, 336, 384, 432, 448, 480, 576, 720, 768, 880, 960, 1056, 1200, 1280, 1344, 1440, 1664, 1680, 1728, 1920, 2112, 2208, 2304, 2400, 2592, 2784, 2880, 3072, 3456, 3840, 4224, 4320

Offset: 1

Jianing Song, Feb 11 2019

nonn

Numbers k in A008330 such that no numbers <= k occur later than k in A008330.

Different from A036912 since a(19) = 144 and A036912(19) = 128.

Cf. A103521.

Cf. also A103203, A121519.

b(n) = if(n==1, 2, floor(exp(Euler)*n*log(log(n^2))+2.5*n/log(log(n^2))));
f(p) = my(i=0); forprime(q=p+1, b(eulerphi(p-1))+1, i+=(eulerphi(q-1)<=eulerphi(p-1))); i;
forprime(p=2, 2e4, if(f(p)==0, print1(eulerphi(p-1), ", ")))

a(n) = phi(A103521(n)-1).

cp's OEIS Frontend

A103203 Primes which have more primitive roots than any smaller prime.

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