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 A008460 Take sum of squares of digits of previous term; start with 6. 14
 6, 36, 45, 41, 17, 50, 25, 29, 85, 89, 145, 42, 20, 4, 16, 37, 58, 89, 145, 42, 20, 4, 16, 37, 58, 89, 145, 42, 20, 4, 16, 37, 58, 89, 145, 42, 20, 4, 16, 37, 58, 89, 145, 42, 20, 4, 16, 37, 58, 89, 145, 42, 20, 4, 16, 37, 58, 89, 145, 42, 20, 4, 16, 37, 58, 89, 145, 42, 20, 4 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 REFERENCES R. Honsberger, Ingenuity in Mathematics, Random House, 1970, p. 83. LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..100 Arthur Porges, A set of eight numbers, Amer. Math. Monthly 52 (1945), 379-382. Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 0, 0, 0, 0, 1). FORMULA Periodic with period 8. a(13+n) = A080709(n). - M. F. Hasler, May 24 2009 MATHEMATICA NestList[Total[IntegerDigits[#]^2]&, 6, 80] (* Vincenzo Librandi, Jan 29 2013 *) PROG (PARI) A008460(n)=[6, 36, 45, 41, 17, 50, 25, 29, 85, 89, 145, 42, 20, 4, 16, 37, 58][if(n<18, n, (n-10)%8+10)] \\ M. F. Hasler, May 24 2009 (Magma) [6, 36, 45, 41, 17, 50, 25, 29, 85] cat &cat[[89, 145, 42, 20, 4, 16, 37, 58]: n in [0..17]]; // Vincenzo Librandi, Jan 29 2013 CROSSREFS Cf. A003132 (the iterated map), A003621, A039943, A099645, A031176, A007770, A000216 (starting with 2), A000218 (starting with 3), A080709 (starting with 4), A000221 (starting with 5), A008462 (starting with 8), A008463 (starting with 9), A139566 (starting with 15), A122065 (starting with 74169). - M. F. Hasler, May 24 2009 Sequence in context: A348384 A328466 A232137 * A132633 A372945 A047792 Adjacent sequences: A008457 A008458 A008459 * A008461 A008462 A008463 KEYWORD nonn,base,easy AUTHOR N. J. A. Sloane EXTENSIONS An erroneous (duplicate) term deleted by M. F. Hasler, May 24 2009 STATUS approved

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Last modified June 17 15:57 EDT 2024. Contains 373463 sequences. (Running on oeis4.)