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A308126 Positive integers equal to the permanent of Hankel matrix formed by their decimal digits.

%I A308126 #7 Feb 16 2025 08:33:55
%S A308126 0,1,2,3,4,5,6,7,8,9,562,962,26240,85440
%N A308126 Positive integers equal to the permanent of Hankel matrix formed by their decimal digits.
%H A308126 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Permanent.html">Permanent</a>
%H A308126 Wikipedia, <a href="https://en.wikipedia.org/wiki/Hankel_matrix">Hankel matrix</a>
%e A308126      | 5 6 2 |
%e A308126 perm | 6 2 6 | = 5*2*5 + 6*6*2 + 2*6*6 + 2*2*2 + 6*6*5 + 5*6*6 = 562.
%e A308126      | 2 6 5 |
%p A308126 with(linalg): P:=proc(q) local c, d, k, n, t: print(0);
%p A308126 for n from 1 to q do c:=convert(n, base, 10): t:=[]:
%p A308126 for k from 1 to nops(c) do t:=[op(t), 0]: od: d:=t: t:=[]:
%p A308126 for k from 1 to nops(c) do t:=[op(t), d]: t[k, -k]:=1: od:
%p A308126 if permanent(evalm(toeplitz(c) &* t))=n then print(n); fi:
%p A308126 od: end: P(10^8);
%Y A308126 Cf. A306714, A306853.
%K A308126 nonn,base,more
%O A308126 1,3
%A A308126 _Paolo P. Lava_, May 14 2019