A239563 Numbers n such that there are a, b with abs(sigma(a) - sigma(b)) = sigma(n) - n and a U b = n, where U is decimal concatenation.

23, 47, 139, 529, 611, 911, 1109, 1445, 1621, 2003, 2521, 2531, 4007, 4361, 4879, 7169, 9011, 9013, 9481, 13009, 18883, 22081, 24257, 25031, 45349, 49901, 56081, 90011, 98941, 99101, 133705, 160031, 169181, 200003, 202289, 210181, 250031, 307289, 336961, 357101

Offset

1,1

Links

Paolo P. Lava and Giovanni Resta, Table of n, a(n) for n = 1..207(terms < 3*10^9, first 50 terms from Paolo P. Lava)

Example

For n = 9481 we can consider 9481 = 9 U 481 and sigma(9481) = 10000, sigma(481) = 532, sigma(9) = 13 and 532 - 13 = 519 = 10000 - 9481.

Maple

with(numtheory);
T:=proc(t) local w, x, y; x:=t; y:=0; while x>0 do x:=trunc(x/10); y:=y+1; od; end:
P:=proc(q) local a, b, c, d, i, n;
for n from 1 to q do a:=sigma(n); b:=T(n);
for i from 1 to b-1 do c:=trunc(n/10^i); d:=n-c*10^i;
if abs(sigma(c)-sigma(d))=a-n then print(n); break; fi;
od; od; end: P(10^9);

Crossrefs

Cf. A000203, A239562.

Sequence in context: A043977 A042048 A347008 * A241207 A042050 A139857

Adjacent sequences: A239560 A239561 A239562 * A239564 A239565 A239566

Keyword

nonn,base

Author

Paolo P. Lava, Mar 21 2014

Status

approved