login
7-white numbers: partition digits of n^7 into blocks of 7 starting at right; sum of these 7-digit numbers equals n.
7

%I #10 Jul 25 2016 00:29:44

%S 0,1,11111110,13477450,20483494,22705717,24588560,25411435,26522546,

%T 27150160,27150161,27777775,28261271,28744768,28888885,28888886,

%U 29372382,29372383,29516500,29855879,31111109,31738723,32078101,32222218,32705716,32849833,33189212,33333331

%N 7-white numbers: partition digits of n^7 into blocks of 7 starting at right; sum of these 7-digit numbers equals n.

%C Seven pairs of consecutive numbers: 27150160 and 27150161; 28888885 and 28888886; 29372382 and 29372383; 35555551 and 35555552; 37777774 and 37777775; 40483492 and 40483493; 41111107 and 41111108.

%C Two sets of three consecutive numbers: 34444440, 34444441 and 34444442; 39999995, 39999996 and 39999997.

%H Paolo P. Lava, <a href="/A274834/b274834.txt">Table of n, a(n) for n = 1..63</a>

%e 11111110^7 = 20907501177620218737880174500399224623868710000000 and

%e 2 + 0907501 + 1776202 + 1873788 + 0174500 + 3992246 + 2386871 + 0000000 = 11111110.

%p P:=proc(q,h) local a,b,n;

%p for n from 0 to q do a:=n^h; b:=0; while a>0 do b:=b+(a mod 10^h); a:=trunc(a/10^h); od;

%p if n=b then print(n); fi; od; end: P(10^6,7);

%Y Cf. A037042-A037045, A274833.

%K nonn,base,fini,full

%O 1,3

%A _Paolo P. Lava_, Jul 08 2016