cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A377471 Smallest prime such that the number of distinct prime factors of its 9's complement is equal to n. If no such number exists return -1.

Original entry on oeis.org

2, 3, 29, 229, 10273, 1000099, 1061069, 101872769, 1569793669, 20207116829, 1069666778189, 102533896856389, 10003581910211789, 1000003754654504609, 100003356331318330889
Offset: 1

Views

Author

Jean-Marc Rebert, Jan 08 2025

Keywords

Examples

			2 is prime, 9-2 = 7 and omega(7) = 1;
		

Crossrefs

Programs

  • PARI
    nc(n) = my(e=length(Str(n))); 10^e-1 - n; \\ A061601
    a(n) = my(p=2); while (omega(nc(p)) != n, p = nextprime(p+1)); p; \\ Michel Marcus, Jan 08 2025

Extensions

a(12)-a(15) from Michael S. Branicky, Jan 12 2025