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A373033
a(0) = 5. For n >= 1, a(n) = a(n-1) converted to base 4 and interpreted in base 10.
2
5, 11, 23, 113, 1301, 110111, 122320133, 13102213110011, 2332222120300201203323, 133212320111123130111021311111121323, 12122133133313032110200332320320202022333020121323230212223, 1323212003321221211122101013133003222123113122111221033300222032132012202011331212030120003001333
OFFSET
0,1
COMMENTS
a(n) is prime for n = 0, 1, 2, 3, 4. What is the next n for which a(n) is prime?
LINKS
Grant Sanderson, How They Fool Ya (live) | Math parody of Hallelujah, 3Blue1Brown YouTube video, 2023.
FORMULA
From Jianing Song, May 22 2024: (Start)
a(n+1) = A007090(a(n)).
As A007090(n+1) = A007090(n) + 1 if n is not congruent to 3 modulo 4, and all terms of A023378 are even, we have a(n) = A023378(n) + 1 by induction. (End)
EXAMPLE
5 --> 11 --> 23 ...
base 10 to base 4 base 10 to base 4
MATHEMATICA
NestList[FromDigits[IntegerDigits[#, 4]] &, 5, 11]
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Paolo Xausa, May 20 2024
STATUS
approved