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A245469 Numbers x such that sigma(x)=sigma(V(x)), where sigma(x) is the sum of the divisors of x and V(x) the transform defined in A245252. 1
432, 537, 3954, 4641, 5394, 7487, 7889, 12640, 20999, 23099, 25990, 35960, 38320, 39479, 41569, 44628, 54880, 58302, 65569, 67172, 73321, 85277, 92939, 106750, 118240, 131652, 153912, 192632, 245019, 258852, 273819, 278389, 303769, 324269, 388494, 393269, 395454 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..37.

EXAMPLE

V(3954) = 7249 and sigma(3954) = sigma(7249) = 7920.

MAPLE

with(numtheory): V:=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; x:=(y[nops(y)]+y[1]) mod 10;

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

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

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

CROSSREFS

Cf. A000203, A243993, A245252, A245468.

Sequence in context: A175026 A205192 A066419 * A069781 A231231 A179666

Adjacent sequences:  A245466 A245467 A245468 * A245470 A245471 A245472

KEYWORD

nonn,base

AUTHOR

Paolo P. Lava, Jul 23 2014

STATUS

approved

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Last modified May 31 09:30 EDT 2020. Contains 334748 sequences. (Running on oeis4.)