

A037156


10^n*(10^n+1)/2.


1



1, 55, 5050, 500500, 50005000, 5000050000, 500000500000, 50000005000000, 5000000050000000, 500000000500000000, 50000000005000000000, 5000000000050000000000, 500000000000500000000000
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OFFSET

0,2


COMMENTS

Sum of first 10^n positive integers.  Omar E. Pol, May 03 2015


REFERENCES

C. Pickover, Wonders of Numbers, Oxford University Press, NY, 2001, p. 328.


LINKS

Table of n, a(n) for n=0..12.
Brian Hayes, Gauss's Day of Reckoning, American Scientist
Bill Johnson, The great Gauss summation trick
C. A. Pickover, "Wonders of Numbers, Adventures in Mathematics, Mind and Meaning," Zentralblatt review


FORMULA

a(n) = A000533(n) * A093143(n).  Omar E. Pol, May 03 2015
From Chai Wah Wu, May 28 2016 : (Start)
a(n) = 110*a(n1)  1000*a(n2).
G.f.: (1  55*x)/((10*x  1)*(100*x  1)).
(End)


EXAMPLE

From Omar E. Pol, May 03 2015: (Start)
For n = 0; a(0) = 1 = 1 * 1 = 1
For n = 1; a(1) = 1 + 2 + ...... + 9 + 10 = 11 * 5 = 55
For n = 2; a(2) = 1 + 2 + .... + 99 + 100 = 101 * 50 = 5050
For n = 3; a(3) = 1 + 2 + .. + 999 + 1000 = 1001 * 500 = 500500
...
(End)


CROSSREFS

A subsequence of the triangular numbers A000217.
Sequence in context: A119081 A119051 A119083 * A116110 A060204 A231783
Adjacent sequences: A037153 A037154 A037155 * A037157 A037158 A037159


KEYWORD

easy,nonn


AUTHOR

Marvin Ray Burns


EXTENSIONS

Corrected by T. D. Noe, Nov 07 2006


STATUS

approved



