A284813 Numbers n such that n' = d_1^k + d_2^(k-2) + ... + d_k^1 where d_1, d_2, ..., d_k are the digits of n, with MSD(n) = d_1 and LSD(n) = d_k, and n' is the arithmetic derivative of n.

4, 766, 2587, 12629, 104977, 1068623, 1844423, 2056849, 2089207, 3126943, 3216923, 3410107, 11894353, 14467237, 20409227, 20544577, 23417957, 53531447, 57145091

Offset

1,1

Links

Table of n, a(n) for n=1..19.

Example

766' = 385 = 7^3 + 6^2 + 6^1.

Maple

with(numtheory): P:=proc(q) local a, k, n, p; for n from 1 to q do a:=convert(n, base, 10);
if add(a[k]^k, k=1..nops(a))=n*add(op(2, p)/op(1, p), p=ifactors(n)[2])
then print(n); fi; od; end: P(10^9);

Crossrefs

Cf. A003415, A284812

Sequence in context: A319943 A181200 A308141 * A306254 A068112 A007725

Adjacent sequences: A284810 A284811 A284812 * A284814 A284815 A284816

Keyword

nonn,base,more

Author

Paolo P. Lava, Apr 07 2017

Status

approved