A301474 Summarize the double of the previous term (digits in increasing order), starting with a(1) = 1.

1, 12, 1214, 221418, 1213241618, 3223242618, 121334153618, 10322314361718, 10322334361718, 10222334461718, 10222344361819, 10222334261738, 1022134415361718, 20323334261728, 10121334255618, 1021421314153618, 20522324261728, 1011121354252618, 3062131425161718

Offset

1,2

Comments

From 56th term the sequence goes into a cycle of 4 terms: 10222334362819, 1022133415361728, 2032233415361718, 20123344461718.

Links

Table of n, a(n) for n=1..19.

Example

a(1) = 1 and 2*1 = 2 ('one 2') then a(2) = 12;
2*12 = 24 ('one 2, one 4') then a(3) = 1214. And so on.

Maple

P:=proc(q, h) local a, b, c, j, k, n; a:=h; print(a);
for n from 1 to q do a:=convert(2*a, base, 10);
b:=0; for k from 0 to 9 do c:=0; for j from 1 to nops(a) do
if a[j]=k then c:=c+1; fi; od;
if c>0 then b:=b*10^(ilog10(c*10+k)+1)+c*10+k; fi; od;
a:=b; print(a); od; end: P(10, 1); # Paolo P. Lava, Mar 22 2018

Crossrefs

Cf. A005151.

Sequence in context: A103269 A317955 A033564 * A054351 A080814 A340834

Adjacent sequences: A301471 A301472 A301473 * A301475 A301476 A301477

Keyword

nonn,base,easy

Author

Paolo P. Lava, Mar 22 2018

Status

approved