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Search: id:A053067
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A053067 a(n) = concatenation of next n numbers (omit leading 0's). +0
17
1, 23, 456, 78910, 1112131415, 161718192021, 22232425262728, 2930313233343536, 373839404142434445, 46474849505152535455, 5657585960616263646566, 676869707172737475767778 (list; graph; listen)
OFFSET

1,2

REFERENCES

Felice Russo, A set of new Smarandache functions, sequences and conjectures in number theory, American Research Press 2000

LINKS

M. L. Perez et al., eds., Smarandache Notions Journal

FORMULA

a(n)=n^2/2+n/2+Sum{k=1..n-1}{(n^2/2+n/2-k)*10^Sum{j=0..k-1}{floor[1+log10(n^2/2+n/2-j)]}} [From Paolo P. Lava (ppl(AT)spl.at), Dec 16 2008]

MAPLE

P:=proc(i) local a, k, j, n; for n from 1 by 1 to i do a:=n^2/2+n/2+sum('(n^2/2+n/2-k)*10^sum('floor(1+evalf(log10(n^2/2+n/2-j)))', 'j'=0..k-1)', 'k'=1..n-1); print(a); od; end: P(100); [From Paolo P. Lava (ppl(AT)spl.at), Dec 16 2008]

CROSSREFS

Sequence in context: A001369 A007923 A080479 this_sequence A036906 A134733 A095256

Adjacent sequences: A053064 A053065 A053066 this_sequence A053068 A053069 A053070

KEYWORD

easy,base,nonn

AUTHOR

Felice Russo (felice.russo(AT)katamail.com), Feb 25 2000

EXTENSIONS

More terms from James A. Sellers (sellersj(AT)math.psu.edu), Feb 28 2000

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Last modified December 18 21:37 EST 2009. Contains 171024 sequences.


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