Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
%I #8 Oct 25 2024 09:22:52
%S 2,3,4,5,7,8,9,10,11,12,13,14,15,16,17,18,19,20,22,23,24,25,26,27,28,
%T 29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,
%U 52,53,54,55,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71
%N Numbers that are not hexateron (5-simplex) numbers.
%C Complement of A000389. Numbers k such that 120*k is not a product of 5 consecutive integers.
%H OEIS wiki, <a href="https://oeis.org/wiki/Simplicial_polytopic_numbers">Simplicial polytopic numbers.</a>
%F a(n) = n+m if n+m>binomial(m+4,5), a(n) = n+m-2 if n+m-2<binomial(m+3,5) and a(n) = n+m-1 otherwise where m = floor((120n)^(1/5)).
%o (Python)
%o from math import comb
%o from sympy import integer_nthroot
%o def A377313(n): return n+(m:=integer_nthroot(120*n,5)[0])+(0 if n>(k:=comb(m+4,5)-m) else -2 if n-2<k-comb(m+3,4) else -1)
%Y Cf. A000389.
%K nonn,easy
%O 1,1
%A _Chai Wah Wu_, Oct 24 2024