The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A273124 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A273124

Numbers n such that the sum of the residues (mod k) of their aliquot parts is equal to n, for some 1 <= k <= n.
(history; published version)

#30 by Bruno Berselli at Fri Jan 13 08:36:49 EST 2017

STATUS

proposed

approved

#29 by Paolo P. Lava at Fri Jan 13 07:55:54 EST 2017

STATUS

editing

proposed

#28 by Paolo P. Lava at Fri Jan 13 07:55:47 EST 2017

MAPLE

with(numtheory): P:= proc(q) local a, b, c, j, k, n;

STATUS

proposed

editing

#27 by Paolo P. Lava at Fri Jan 13 07:55:02 EST 2017

STATUS

editing

proposed

#26 by Paolo P. Lava at Fri Jan 13 07:24:01 EST 2017

MAPLE

with(numtheory): P:= proc(q) local a, b, c, j, k, n; for n from 1 to q do a:=sort([op(divisors(n))]); c:=sigma(n)-2*n;

for n from 1 to q do a:=sort([op(divisors(n))]);

for k from 1 to n do if type(c/k, integer) then b:=0; for j from 1 to nops(a)-1 do b:=b+(a[j] mod k); od;

b:=b+(a[j] mod k); od; if b=n then print(n); break; fi; fi; od; od; end: P(10^5);

STATUS

approved

editing

#25 by N. J. A. Sloane at Sat May 21 22:41:49 EDT 2016

STATUS

proposed

approved

#24 by Paolo P. Lava at Fri May 20 10:13:59 EDT 2016

STATUS

editing

proposed

#23 by Paolo P. Lava at Fri May 20 10:12:54 EDT 2016

LINKS

Paolo P. Lava, <a href="/A273124/a273124_1.txt">First 50 100 terms with 3 different values for of k >= 3</a>

STATUS

proposed

editing

#22 by Paolo P. Lava at Thu May 19 02:58:06 EDT 2016

STATUS

editing

proposed

#21 by Paolo P. Lava at Thu May 19 02:57:23 EDT 2016

MAPLE

with(numtheory): P:= proc(q) local a, b, c, j, k, n; for n from 1 to q do a:=sort([op(divisors(n))]); c:=sigma(n)-2*n;

for k from 1 to n do if type(c/k, integer) then b:=0; for j from 1 to nops(a)-1 do b:=b+(a[j] mod k); od;

if b=n then print(n); break; fi; fi; od; od; end: P(10^5);

STATUS

proposed

editing

Discussion

Thu May 19

02:58

Paolo P. Lava: Updated Maple code according to Robert's suggestion