cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A254009 Numbers that divide the sum of the reverse of their aliquot parts (A069250).

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%I A254009 #20 Nov 09 2018 02:47:36
%S A254009 1,6,244,285,944,1242,3738,22644,37686,58950,85512,124944,130410,
%T A254009 133857,235644,3202101,5367582,5663697,45165231,141635817,214939686,
%U A254009 736140702,2395863144,4992033177,28406362140,30364415451
%N A254009 Numbers that divide the sum of the reverse of their aliquot parts (A069250).
%C A254009 A072228 is a subsequence. - _Paolo P. Lava_, Nov 09 2018
%e A254009 Aliquot parts of 944 are 1, 2, 4, 8, 16, 59, 118, 236, 472 and the sum of their reverse is 1 + 2 + 4 + 8 +61 + 95 + 811 + 632 + 274 = 1888. Finally, 1888 / 944 = 2.
%p A254009 with(numtheory):
%p A254009 T:=proc(w) local x,y,z; x:=w; y:=0;
%p A254009 for z from 1 to ilog10(x)+1 do y:=10*y+(x mod 10); x:=trunc(x/10); od; y; end:
%p A254009 P:=proc(q) local a,b,k; global n;
%p A254009 for n from 1 to q do a:=sort([op(divisors(n))]); b:=add(T(a[k]),k=1..nops(a)-1);
%p A254009 if type(b/n,integer) then print(n); fi; od; end: P(10^9);
%o A254009 (PARI) isok(n) = (sumdiv(n, d, (d != n)* eval(concat(Vecrev(Str(d))))) % n) == 0; \\ _Michel Marcus_, Feb 27 2015
%Y A254009 Cf. A069250, A072228, A007691, A254008.
%K A254009 nonn,base
%O A254009 1,2
%A A254009 _Paolo P. Lava_, Jan 22 2015
%E A254009 a(16)-a(26) from _Lars Blomberg_, Feb 27 2015