

A061098


Concatenation of all numbers less than or equal to n other than the phi(n) numbers relatively prime to n.


1



1, 2, 3, 24, 5, 2346, 7, 2468, 369, 2456810, 11, 2346891012, 13, 24678101214, 3569101215, 246810121416, 17, 234689101214151618, 19, 2456810121415161820, 36791214151821, 24681011121416182022, 23, 23468910121415161820212224, 510152025, 246810121314161820222426
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OFFSET

1,2


COMMENTS

a(1) = 1 as the number itself is to be included. a(p) = p if p is a prime (by definition).


LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..100


EXAMPLE

a(6) = 2346, as 2,3,4,6 are not coprime to 6 and 1 and 5 are coprime to 6.


PROG

(PARI) a(n)={if(n==1, 1, fromdigits(concat([digits(k)  k<[1..n], gcd(k, n)>1])))} \\ Andrew Howroyd, Nov 09 2019


CROSSREFS

Cf. A000010.
Sequence in context: A001783 A095996 A308943 * A160630 A119619 A170909
Adjacent sequences: A061095 A061096 A061097 * A061099 A061100 A061101


KEYWORD

nonn,base


AUTHOR

Amarnath Murthy, Apr 19 2001


EXTENSIONS

Offset corrected and terms a(14) and beyond from Andrew Howroyd, Nov 09 2019


STATUS

approved



