A290148 - OEIS

A290148

a(n) is the integer resulting from the concatenation of the unit digit of n-1 to the digits of n without its own unit digit.

0, 1, 2, 3, 4, 5, 6, 7, 8, 91, 1, 11, 21, 31, 41, 51, 61, 71, 81, 92, 2, 12, 22, 32, 42, 52, 62, 72, 82, 93, 3, 13, 23, 33, 43, 53, 63, 73, 83, 94, 4, 14, 24, 34, 44, 54, 64, 74, 84, 95, 5, 15, 25, 35, 45, 55, 65, 75, 85, 96, 6, 16, 26, 36, 46, 56, 66, 76, 86, 97, 7

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OFFSET

1,3

COMMENTS

Take list of integers n >= 1, move right digit of each term to left end of next term.

LINKS

Table of n, a(n) for n=1..71.

FORMULA

a(n) = (n -1 mod 10)*10^A004216(n) + floor(n/10). # Robert Israel, Jul 21 2017

EXAMPLE

For n=46, n-1 is 45, so a(46) is the concatenation of 5 (the unit digit of 45) and 4 (46 without 6), giving 54.

For n=123, n-1 is 122, so a(123) is the concatenation of 2 (the unit digit of 122) and 12 (123 without 3), giving 212.

MAPLE

f:= n -> (n-1 mod 10) * 10^ilog10(n) + floor(n/10);

PROG

(PARI) a(n) = my(precd = (n-1)%10); if (n < 10, precd, eval(concat(Str(precd), Str(n\10))));

CROSSREFS

Cf. A004216, A032762.

Sequence in context: A331879 A098755 A028430 * A171717 A303369 A154701

Adjacent sequences: A290145 A290146 A290147 * A290149 A290150 A290151

KEYWORD

nonn,base

AUTHOR

Michel Marcus, Jul 21 2017

STATUS

approved