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.
%I A076848 #32 Apr 17 2025 23:17:30 %S A076848 73,4832936419,157,20794121,127,859493,557,113,3221,19,7549,43,17,61, %T A076848 211,241,18617,907,419,47,443,911,47955653711170550856726386495271851, %U A076848 1109,53,31,37,2543,19,17,617,33521,23,7906914473,38851,421,39640576062095087 %N A076848 Smallest prime factor of googol + n that exceeds 13, or 1 if googol + n is 13-smooth. %C A076848 A googol is 10^100. Factors found using PARI and Dario Alpern's ECM factorization applet. %H A076848 Sean A. Irvine, <a href="/A076848/b076848.txt">Table of n, a(n) for n = 1..1000</a> (terms 1..400 from Charles R Greathouse IV, n=260 corrected by Sean A. Irvine) %H A076848 Dario Alpern, <a href="https://www.alpertron.com.ar/ECM.HTM">Factorization using the Elliptic Curve Method</a> %F A076848 a(n) = A020639(A007947(10^100 + n)/gcd(10^100 + n, A034386(13))), where A020639(m) = lpf(m), smallest prime factor of m. - _Peter Munn_, Feb 20 2025 %Y A076848 Cf. A049014 (n such that googol + n is prime), A066298, A080197 (relates to positions of 1's). %Y A076848 Equivalent sequences: A072288 (googolplex + n), A078813 (googol - n). %Y A076848 See the formula section for the relationships with A007947, A020639, A034386. %K A076848 nonn %O A076848 1,1 %A A076848 _Jason Earls_, Nov 23 2002 %E A076848 a(23) found by _Sean A. Irvine_ on Dec 08 2002 by employing SNFS, using the polynomials x^5+23 and x-10^20. %E A076848 Edited by _Robert G. Wilson v_, Dec 09 2002 %E A076848 Edited by _Peter Munn_, Feb 20 2025