

A255968


Numbers n such that antisigma(n) contains n as a substring.


1



24, 57, 204, 411, 559, 2004, 2440, 3935, 6616, 8640, 20004, 34939, 55827, 61009, 64599, 79747, 87113, 87269, 96513, 481557, 621265, 647532, 702893, 704682, 797465, 2000004, 2385120
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OFFSET

1,1


COMMENTS

Any number of the form 20...04, with a number of consecutive zeros not equal to 6*k+4 (with k = 0, 1, 2, 3,...), appears to belong to the sequence.


LINKS

Table of n, a(n) for n=1..27.


EXAMPLE

antisigma(24) = (24*25) / 2  sigma(24) = 300  60 = 240 and 24 is a substring;
antisigma(57) = (57*58) / 2  sigma(57) = 1653  80 = 1573 and 57 is a substring.


MAPLE

with(numtheory): P:=proc(q) local a, b, c, d, j, n;
for n from 1 to q do a:=n; b:=n*(n+1)/2sigma(n); c:=ilog10(n)+1; d:=ilog10(b)+1;
for j from 1 to dc+1 do if n=(b mod 10^c) then print(n); break; else b:=trunc(b/10);
fi; od; od; print(); end: P(10^9);


CROSSREFS

Cf. A024816.
Sequence in context: A208086 A232937 A190104 * A211325 A290303 A044126
Adjacent sequences: A255965 A255966 A255967 * A255969 A255970 A255971


KEYWORD

nonn,base


AUTHOR

Paolo P. Lava, Mar 12 2015


STATUS

approved



