A076069 - OEIS

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A076069

Largest number formed as concatenation of a permutation of the n consecutive numbers 1+n(n-1)/2, ..., n(n+1)/2 (written in decimal).

1, 32, 654, 98710, 1514131211, 212019181716, 28272625242322, 3635343332313029, 454443424140393837, 55545352515049484746, 6665646362616059585756, 787776757473727170696867, 91908988878685848382818079, 9998979695949392105104103102101100

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OFFSET

1,2

COMMENTS

Nontrivial (i.e., different from concatenation in reverse order) whenever a number of the form 10^k is in the considered range of n numbers; then a(n) is given as concatenation (10^k-1)...(1+n(n-1)/2)(n(n+1)/2)...(10^k).

LINKS

Table of n, a(n) for n=1..14.

EXAMPLE

1, then a concatenation of a permutation of 2 and 3, then a concatenation of a permutation of 4, 5 and 6.

PROG

(PARI 2.4.2) a(n)=eval(concat(vecsort(vector(n, i, Str(i+n*(n-1)/2)), , 4)))

CROSSREFS

Cf. A076068, A080479, A080480, A192392.

Sequence in context: A028183 A192392 A076072 * A080480 A028152 A028176

Adjacent sequences: A076066 A076067 A076068 * A076070 A076071 A076072

KEYWORD

nonn,easy,less,base

AUTHOR

M. F. Hasler, Jun 29 2011

EXTENSIONS

Definition modified to obtain a new sequence different from (earlier duplicate) A080480. M. F. Hasler, Jun 29 2011.

STATUS

approved