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A213240 Numbers n such that sum of digits of n = sum of digits of n’, where n’ is the arithmetic derivative of n. 2
4, 22, 27, 54, 56, 81, 94, 108, 121, 135, 166, 202, 216, 243, 245, 260, 265, 266, 272, 274, 308, 344, 346, 355, 382, 405, 445, 454, 459, 513, 517, 518, 526, 562, 567, 594, 634, 648, 675, 702, 706, 729, 784, 806, 832, 837, 841, 891, 913, 920, 922, 945, 950, 972 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Paolo P. Lava, Table of n, a(n) for n = 1..10000

EXAMPLE

n=344 and 3+4+4=11; n’=524 and 5+2+4=11.

MAPLE

with(numtheory);

A213240:=proc(q)

local a, b, d, n, p, pfs;

for n from 1 to q do

  pfs:=ifactors(n)[2]; a:=n*add(op(2, p)/op(1, p), p=pfs); b:=0;

  while a>0 do b:=b+(a mod 10); a:=trunc(a/10); od;

  a:=n; d:=0; while a>0 do d:=d+(a mod 10); a:=trunc(a/10); od;

  if b=d then print(n); fi;

od; end:

A213240(100000000);

CROSSREFS

Cf. A003415, A006753, A213239

Sequence in context: A059653 A022385 A244411 * A279314 A006753 A098836

Adjacent sequences:  A213237 A213238 A213239 * A213241 A213242 A213243

KEYWORD

nonn,base

AUTHOR

Paolo P. Lava, Jun 07 2012

STATUS

approved

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Last modified March 29 17:23 EDT 2020. Contains 333116 sequences. (Running on oeis4.)