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URL: https://oeis.org/A112375

⇱ A112375 - OEIS

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A112375
Concatenation of base and exponent of prime powers.
3
21, 31, 22, 51, 71, 23, 32, 111, 131, 24, 171, 191, 231, 52, 33, 291, 311, 25, 371, 411, 431, 471, 72, 531, 591, 611, 26, 671, 711, 731, 791, 34, 831, 891, 971, 1011, 1031, 1071, 1091, 1131, 112, 53, 1271, 27, 1311, 1371, 1391, 1491, 1511, 1571, 1631, 1671
OFFSET
1,1
COMMENTS
If n = p^q, where p is prime and q > 0, then p concatenated with q is in the sequence.
Might be a good "puzzle" sequence - guess the rule given the first ten or so terms.
LINKS
FORMULA
a(n) = A067599(A246655(n)) = A067599(A000961(n+1)). - M. F. Hasler, Mar 14 2018
EXAMPLE
n = 3 = 3^1, so (3 concatenated with 1) = 31 is a term.
MATHEMATICA
Map[FromDigits, Select[Table[FactorInteger[i], {i, 2, 10000}],
Length[#] == 1 &], 2] (* Robert Price, Mar 15 2020 *)
PROG
(PARI) for(n=1, 300, fac=factor(n); if(matsize(fac)[1]==1, print1(eval(concat(Str(fac[1, 1]), Str(fac[1, 2]))), ", ")))
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Dec 04 2005
EXTENSIONS
Edited and extended by Klaus Brockhaus, Jan 21 2006
STATUS
approved