A341803 a(n) is the least k such that A076620(k) = n.

1, 2, 7, 24, 72, 203, 564, 1556, 4274, 11709, 32021, 87463, 238691

Offset

0,2

Comments

Conjecture: Starting at 7, terms coincide with A309237 - 1. - Hugo Pfoertner, Feb 21 2021

Links

Table of n, a(n) for n=0..12.

Formula

a(n) ~ c*e^n.

Example

a(4) = 24 as A076620(24) = 4 while A076620(k) < 4 for k < 24.

Mathematica

With[{s = Array[-1 + FirstPosition[#, Max[#]][[1]] &@ CoefficientList[Pochhammer[x, #]/x, x] &, 600]}, {1}~Join~Array[-1 + FirstPosition[s, #][[1]] &, Max@ s]] (* Michael De Vlieger, Feb 22 2021 *)

Prog

(PARI) first(n) = {res = vector(n); res[1] = 1; my(r = 1); print1(1", "); v = [1]; for(i = 1, oo, v = concat(0, v) + concat(v, 0)*i; if(#v > n, v = v[^-1]; ); for(j = r + 1, #v, if(v[j] > v[j - 1], r++; res[r] = i; print1(i", "); if(r >= n, return(res); ) , next ))); res }

Crossrefs

Cf. A076620.

Sequence in context: A054128 A082047 A370306 * A375273 A272483 A129020

Adjacent sequences: A341800 A341801 A341802 * A341804 A341805 A341806

Keyword

nonn,more

Author

David A. Corneth, Feb 20 2021

Status

approved