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 A195201 a(n) is the largest prime factor of the number made by taking the previous term and duplicating the final digit, a(1) = 1. 0
 1, 11, 37, 29, 23, 233, 2333, 23333, 661, 601, 6011, 6679, 997, 907, 313, 241, 2411, 47, 53, 41, 137, 17, 59, 599, 857, 953, 9533, 13619, 19457, 821, 23, 233, 2333, 23333, 661, 601, 6011, 6679, 997, 907, 313, 241, 2411, 47, 53, 41, 137, 17, 59, 599, 857, 953 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS This sequence is periodic with period (23, 233, 2333, 23333, 661, 601, 6011, 6679, 997, 907, 313, 241, 2411, 47, 53, 41, 137, 17, 59, 599, 857, 953, 9533, 13619, 19457, 821) of length 26. LINKS Table of n, a(n) for n=1..52. Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1). EXAMPLE Next term after 11 is 37 because 111 = 3*37. Next term after 37 is 29 because 377 = 13*29. Next term after 821 is 23 because 8211 = 3*7*17*23. MATHEMATICA NestList[FactorInteger[10#+Mod[#, 10]][[-1, 1]]&, 11, 60](* Zak Seidov, Sep 16 2011*) CROSSREFS Sequence in context: A191296 A052526 A306498 * A233403 A054293 A072859 Adjacent sequences: A195198 A195199 A195200 * A195202 A195203 A195204 KEYWORD nonn,base,easy AUTHOR J. Lowell, Sep 12 2011 EXTENSIONS a(1) prepended by Zak Seidov, Sep 18 2011 STATUS approved

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Last modified June 7 21:29 EDT 2023. Contains 363157 sequences. (Running on oeis4.)