

A121280


Position where concatenate(1,...,n) occurs for the first time in the decimals of Pi (where 3, 1, 4,... are at position 0, 1, 2,...).


14



1, 148, 1924, 13807, 49702, 2458885, 9470344, 186557266, 523551502, 191278379839, 4368196101671
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OFFSET

1,2


COMMENTS

This sequence uses the same convention for the "position" as sequences A035117, A050279  A050287, A048940, A096755  A096763, while A068987(n) = a(n)+1 counts the positions of 3,1,4,.... as 1,2,3,...  M. F. Hasler, Mar 18 2017
a(10) > 2*10^9.  M. F. Hasler, Apr 13 2019
a(12) > 22*10^12.  Dmitry Petukhov, Jan 29 2020


LINKS

Table of n, a(n) for n=1..11.
Dave G. Andersen, The PiSearch Page
Subidiom.com, Irrational numbers search engine: π = 3.14159...
Peter Trüb, 22.4 trillion digits of pi


FORMULA

a(n) = A068987(n)  1.


CROSSREFS

First occurrence of n times the same digit: A035117 (n '1's), A050281 (n '2's), A050282, A050283, A050284, A050286, A050287, A048940 (n '9's).
First occurrence of exactly n times the same digit: A096755 (exactly n '1's), A096756, A096757, A096758, A096759, A096760, A096761, A096762, A096763 (exactly n '9's), A050279 (exactly n '0's).
Cf. A176341: first occurrence of n; A121280 = A068987  1: first occurrence of concatenate(1,...,n).
Cf. A000796: Decimal expansion (or digits) of Pi.
Sequence in context: A186894 A233727 A178264 * A338970 A224260 A223916
Adjacent sequences: A121277 A121278 A121279 * A121281 A121282 A121283


KEYWORD

nonn,base,more


AUTHOR

Alexander R. Povolotsky, Nov 03 2007


EXTENSIONS

New definition and crossreferences from M. F. Hasler, Mar 18 2017
Additional term a(9), using subidiom search engine, from M. F. Hasler, Apr 13 2019
a(10)a(11) from Dmitry Petukhov, Jan 16 2020


STATUS

approved



