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 A181062 #48 Apr 26 2024 01:38:10 %S A181062 0,1,2,3,4,6,7,8,10,12,15,16,18,22,24,26,28,30,31,36,40,42,46,48,52, %T A181062 58,60,63,66,70,72,78,80,82,88,96,100,102,106,108,112,120,124,126,127, %U A181062 130,136,138,148,150,156,162,166,168,172,178,180,190,192,196,198,210,222,226 %N A181062 Prime powers minus 1. %C A181062 If 0 is excluded, a(n) gives the possible lengths of the longest string of consecutive divisors of a positive integer: range of values of A055874. %C A181062 a(n) is the largest number m such that A051451(n) = A003418(m). %C A181062 From _Jianing Song_, Nov 01 2023: (Start) %C A181062 Let q = A000961(n) for n > 1. Then: %C A181062 - a(n) is the number of units in the finite field F_q. %C A181062 - a(n) is the number of solutions to x*y = t for any t != 0 in F_q. %C A181062 - If q is odd, then a(n) is also the number of solutions to x^2 - y^2 = t for any t != 0 in F_q. (End) %H A181062 Matthew House, <a href="/A181062/b181062.txt">Table of n, a(n) for n = 1..10000</a> %F A181062 a(n) = A000961(n)-1. %e A181062 Any integer that is divisible by 5 consecutive integers will be divisible by at least 6 consecutive integers. Hence 5 is not in the sequence. %t A181062 Join[{0}, Select[Range@225, PrimePowerQ] - 1] (* _Ivan Neretin_, Aug 04 2016 *) %o A181062 (PARI) isA181062(n)=ispower(n++,,&n);isprime(n) \\ _Charles R Greathouse IV_, Jun 29 2011 %o A181062 (PARI) isok(n) = (n==0) || isprimepower(n++); \\ _Michel Marcus_, Aug 05 2016 %Y A181062 Cf. A000961, A181063, A181064, A181121. %Y A181062 Includes A006093 as a subsequence. %Y A181062 Cf. A003418, A051451, A055874. %K A181062 easy,nonn %O A181062 1,3 %A A181062 _Matthew Vandermast_, Oct 07 2010 %E A181062 Entry revised by _N. J. A. Sloane_, Jan 06 2013