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A245468 Numbers x such that sigma(x)=sigma(T(x)), where sigma(x) is the sum of the divisors of x and T(x) the transform defined in A243993. 1
204, 395, 506, 583, 612, 627, 718, 795, 975, 2012, 3188, 3690, 7198, 7881, 11472, 21280, 34040, 41310, 49021, 53314, 94363, 107348, 128616, 201804, 203912, 204204, 204435, 207390, 315244, 321010, 345990, 347484, 388297, 395395, 400020, 400352, 402815, 404576 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..38.

EXAMPLE

T(3188) = 4961 and sigma(3188) = sigma(4961) = 5586.

MAPLE

with(numtheory);

T:=proc(t) local j, w, x, y; x:=t; y:=[]; while x>0 do

y:=[x mod 10, op(y)]; x:=trunc(x/10); od; w:=(y[nops(y)]+y[1]) mod 10;

x:=0; for j from 1 to nops(y)-1 do x:=x*10+((y[j]+y[j+1]) mod 10); od; x:=x*10+w; end:

P:=proc(q) local n; for n from 10 to q do if sigma(n)=sigma(T(n))

then print(n); fi; od; end: P(10^10);

CROSSREFS

Cf. A000203, A243993, A245252, A245469.

Sequence in context: A271643 A108877 A163393 * A154518 A249285 A292346

Adjacent sequences:  A245465 A245466 A245467 * A245469 A245470 A245471

KEYWORD

nonn,base

AUTHOR

Paolo P. Lava, Jul 23 2014

STATUS

approved

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Last modified April 23 14:15 EDT 2019. Contains 322386 sequences. (Running on oeis4.)