A037139 Deficient numbers k such that k-s(k)-s(k-s(k)) = s(s(k))-s(k) or s(k-s(k))-k+s(k) = s(k)-s(s(k)).

123, 285, 734, 1437, 2733, 926875, 2122173, 21466939, 797141342

Offset

1,1

Comments

Here s(k) = sigma(k) - k (see A001065).

a(10) > 10^10, if it exists. - Amiram Eldar, Mar 14 2024

Links

Table of n, a(n) for n=1..9.

Prog

(PARI) s(n) = sigma(n) - n;
is(n) = {my(s1 = s(n)); if(s1 >= n, 0, n - s1 - s(n-s1) == s(s1) - s1); } \\ Amiram Eldar, Mar 14 2024

Crossrefs

Cf. A001065, A005100.

Sequence in context: A004945 A004965 A216382 * A269751 A235133 A179612

Adjacent sequences: A037136 A037137 A037138 * A037140 A037141 A037142

Keyword

nonn,more

Author

Naohiro Nomoto

Extensions

More terms from Jason Earls, Aug 30 2001

Offset corrected, wrong term removed and a(8)-a(9) added by Amiram Eldar, Mar 14 2024

Status

approved