The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A257751 Quasi-Carmichael numbers to exactly one base. 11
 35, 77, 143, 165, 187, 209, 231, 247, 273, 299, 357, 391, 399, 437, 493, 527, 561, 589, 598, 713, 715, 943, 989, 1015, 1073, 1189, 1247, 1295, 1333, 1537, 1547, 1705, 1729, 1739, 1829, 1886, 1927, 1961, 2015, 2021, 2257, 2279, 2387, 2397, 2419, 2451, 2479, 2501 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS See A259238 for the corresponding bases. LINKS Tim Johannes Ohrtmann, Table of n, a(n) for n = 1..14688 EXAMPLE a(1) = 35 because this is the first squarefree composite number n such that exactly one nonzero integer b exists such that for every prime factor p of n, p+b divides n+b (-3): 35=5*7 and 2, 4 both divide 32. PROG (PARI) for(n=2, 1000000, if(!isprime(n), if(issquarefree(n), f=factor(n); k=0; for(b=-(f[1, 1]-1), n, c=0; for(i=1, #f[, 1], if((n+b)%(f[i, 1]+b)>0, c++)); if(c==0, if(!b==0, k++))); if(k==1, print1(n, ", "))))) CROSSREFS Cf. A257750 (every number of bases). Cf. A257752, A257753, A257754, A257755, A257756, A257757, A258842 (2 to 8 bases). Cf. A257758 (first occurrences). Sequence in context: A254443 A300160 A257750 * A259282 A201068 A111144 Adjacent sequences:  A257748 A257749 A257750 * A257752 A257753 A257754 KEYWORD nonn AUTHOR Tim Johannes Ohrtmann, May 07 2015 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified January 22 14:29 EST 2022. Contains 350481 sequences. (Running on oeis4.)