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A186506
An example of a pyramid of numbers that starts with 1 and successive terms are primes formed by inserting the next power of 3 somewhere in the previous term.
1
1, 13, 139, 12739, 1281739, 1281739243, 1281737299243, 12817372218799243, 128173765612218799243, 12196838173765612218799243, 1219683817376590495612218799243, 1219683817714717376590495612218799243, 1219683853144117714717376590495612218799243, 12196838531441159432317714717376590495612218799243, 121968385314411594323177147478296917376590495612218799243
OFFSET
0,2
COMMENTS
This is not really well-defined, but it is a published sequence of some recreational interest.
REFERENCES
C. K. Caldwell and A. Rupinski, Pyramids of 3-powerful primes, Mathematical Spectrum, 43 (No. 2, 2010/2011), 65-69.
LINKS
C. K. Caldwell and A. Rupinski, Pyramids of 3-powerful primes (abstract), Mathematical Spectrum, 43 (No. 2, 2010/2011), 65-69.
EXAMPLE
(1)
13
139
12739
1281739
1281739243
1281737299243
12817372218799243
128173765612218799243
12196838173765612218799243
1219683817376590495612218799243
1219683817714717376590495612218799243
1219683853144117714717376590495612218799243
12196838531441159432317714717376590495612218799243
121968385314411594323177147478296917376590495612218799243
CROSSREFS
Cf. A186507.
Sequence in context: A365999 A064103 A266630 * A051639 A138931 A157160
KEYWORD
base,nonn,fini,full
AUTHOR
N. J. A. Sloane, Feb 22 2011
STATUS
approved