A293479 Composite numbers k = concat(MSD(k),x) such that the sum of the aliquot parts of k is equal to the sum of the aliquot parts of x.

1219, 1339, 3959, 4189, 7519, 11569, 11947, 27347, 35579, 37391, 38579, 45391, 46097, 77593, 81407, 94319, 94807, 95299, 96139, 97271, 99691, 102937, 106159, 107629, 115069, 131917, 137533, 158221, 168637, 201659, 223997, 339629, 345911, 352829, 362771, 363191

Offset

1,1

Links

Table of n, a(n) for n=1..36.

Example

sigma(27347) - 27347 = 30240 - 27347 = 2893 and sigma(7347) - 7347 = 10240 - 7347 = 2893.

Maple

with(numtheory): P:=proc(q) local a, k, n, p, x, y; for n from 2 to q do
if not isprime(n) then x:=n mod 10^(ilog10(n));
if sigma(n)-n=sigma(x)-x then print(n); fi; fi; od; end: P(10^6);

Crossrefs

Cf. A000030, A000203, A001065.

Sequence in context: A175964 A300408 A252600 * A031781 A069400 A233660

Adjacent sequences: A293476 A293477 A293478 * A293480 A293481 A293482

Keyword

nonn,base,easy

Author

Paolo P. Lava, Oct 10 2017

Status

approved