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 A039790 Prime numbers prefixed with a '1'. 2
 12, 13, 15, 17, 111, 113, 117, 119, 123, 129, 131, 137, 141, 143, 147, 153, 159, 161, 167, 171, 173, 179, 183, 189, 197, 1101, 1103, 1107, 1109, 1113, 1127, 1131, 1137, 1139, 1149, 1151, 1157, 1163, 1167, 1173, 1179, 1181, 1191, 1193, 1197, 1199, 1211 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Replace every prime by the concatenation of its divisors. [Lekraj Beedassy, May 29 2009] LINKS David F. Marrs, Table of n, a(n) for n = 1..10000 Kevin N. Stone, What number comes next in this sequence, BrainBashers [Archived copy at the Wayback Machine]. FORMULA a(n) = A037278(A000040(n)). [Lekraj Beedassy, May 29 2009] MATHEMATICA Array[10^Floor[1 + Log10[#]] + # &@ Prime[#] &, 47] (* Michael De Vlieger, Apr 05 2021 *) PROG (PARI) a(n) = eval(concat(Str(1), Str(prime(n)))) \\ Felix Fröhlich, Apr 05 2021 CROSSREFS Cf. A000040, A037278, A289866 (terms which are prime). Sequence in context: A262210 A074164 A076085 * A242912 A102496 A267615 Adjacent sequences: A039787 A039788 A039789 * A039791 A039792 A039793 KEYWORD nonn,base,dumb AUTHOR Kevin N. Stone (kevin.stone(AT)brainbashers.com) STATUS approved

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Last modified July 25 15:49 EDT 2024. Contains 374612 sequences. (Running on oeis4.)