A052246 Concatenation of integers from n down to 0.

0, 10, 210, 3210, 43210, 543210, 6543210, 76543210, 876543210, 9876543210, 109876543210, 11109876543210, 1211109876543210, 131211109876543210, 14131211109876543210, 1514131211109876543210, 161514131211109876543210, 17161514131211109876543210

Offset

0,2

Links

Table of n, a(n) for n=0..17.

Formula

a(0)=0, a(n) = n*10^len(a(n-1)) + a(n-1), where len(k) = number of digits in k and len(0)=1; = A000422*10.

Maple

a:= proc(n) a(n):= `if`(n=0, 0, parse(cat(n, a(n-1)))) end:
seq(a(n), n=0..22);  # Alois P. Heinz, Jan 12 2021

Mathematica

nn=20; With[{c=Range[nn, 0, -1]}, Table[FromDigits[Flatten[ IntegerDigits/@ Take[ c, -n]]], {n, nn}]] (* Harvey P. Dale, Feb 01 2013 *)

Prog

(PARI) /* computation by definition: */
a(n)=if(n==0, 0, eval(Str(n, a(n-1)))); \\ Joerg Arndt, Sep 14 2014

Crossrefs

Cf. A000422.

Sequence in context: A067642 A334537 A052245 * A001450 A076803 A120596

Adjacent sequences: A052243 A052244 A052245 * A052247 A052248 A052249

Keyword

base,easy,nonn

Author

Henry Bottomley, Feb 01 2000

Status

approved