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A248819 Numbers n such that the digits of antisigma(n) end in sigma(n). 0
79, 479, 2879, 4895, 26879, 79999, 644735, 799999, 2395488, 6399839, 8598719, 63652895, 144726608, 799999999, 935546879, 12640160863, 15282380799, 43687707904, 79999999999 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All the primes of the form 8*10^k-1 for k>0 are terms (A056721). - Giovanni Resta, May 29 2016

LINKS

Table of n, a(n) for n=1..19.

EXAMPLE

sigma(4895) = 6480 and antisigma of 4895 is (4895 * 4896) / 2 - sigma(4895) = 11982960 - 6480 = 11976480.

MAPLE

with(numtheory): P:=proc(q) local a, n;

for n from 1 to q do then a:=ilog10(sigma(n))+1;

if sigma(n)=((n*(n+1)/2-sigma(n)) mod 10^a) then print(n);

fi; od; end: P(10^9);

CROSSREFS

Cf. A000230, A024816, A056721.

Sequence in context: A142556 A023315 A142618 * A141563 A107954 A098673

Adjacent sequences:  A248816 A248817 A248818 * A248820 A248821 A248822

KEYWORD

nonn,more,base

AUTHOR

Paolo P. Lava, Oct 15 2014

EXTENSIONS

a(9)-a(19) from Giovanni Resta, May 29 2016

STATUS

approved

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Last modified March 25 15:02 EDT 2019. Contains 321470 sequences. (Running on oeis4.)