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A248818 Numbers n such that the digits of antisigma(n) end in phi(n). 0
3, 20, 39, 119, 224, 351, 799, 879, 1076, 1504, 4064, 6879, 7999, 56847, 169640, 346879, 470975, 893520, 1955776, 7546879, 17604064, 36722175, 79999999, 95546879, 222503984, 580483743, 584057247, 626394816, 7999999999, 17194139104 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Similar to A024816 but using antisigma(n) instead of sigma(n).

All the semiprimes of the form 8*10^k-1 are terms. - Giovanni Resta, May 29 2016

LINKS

Table of n, a(n) for n=1..30.

EXAMPLE

Antisigma of 879 is (879 * 880) / 2 - sigma(879) = 386760 - 1176 = 385584 and phi(879) = 584.

MAPLE

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

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

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

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

CROSSREFS

Cf. A000010, A024816.

Sequence in context: A254501 A031106 A337478 * A268602 A267055 A296252

Adjacent sequences:  A248815 A248816 A248817 * A248819 A248820 A248821

KEYWORD

nonn,base

AUTHOR

Paolo P. Lava, Oct 15 2014

EXTENSIONS

a(18)-a(30) from Giovanni Resta, May 29 2016

STATUS

approved

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Last modified September 28 02:03 EDT 2020. Contains 337392 sequences. (Running on oeis4.)