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 A048572 a(n) = sum of digits of a(n-1)*a(n-2). 1
 1, 2, 2, 4, 8, 5, 4, 2, 8, 7, 11, 14, 10, 5, 5, 7, 8, 11, 16, 14, 8, 4, 5, 2, 1, 2, 2, 4, 8, 5, 4, 2, 8, 7, 11, 14, 10, 5, 5, 7, 8, 11, 16, 14, 8, 4, 5, 2, 1, 2, 2, 4, 8, 5, 4, 2, 8, 7, 11, 14, 10, 5, 5, 7, 8, 11, 16, 14, 8, 4, 5, 2 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS This sequence is periodic with period 24. - T. D. Noe, Feb 15 2008 LINKS 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, 1). FORMULA a(n)=(1/6624)*{439*(n mod 24)+991*[(n+1) mod 24]-113*[(n+2) mod 24]+1267*[(n+3) mod 24]+1819*[(n+4) mod 24]+715*[(n+5) mod 24]-1217*[(n+6) mod 24]-665*[(n+7) mod 24]-113*[(n+8) mod 24]-389*[(n+9) mod 24]+163*[(n+10) mod 24]+1543*[(n+11) mod 24]+1267*[(n+12) mod 24]-665*[(n+13) mod 24]-941*[(n+14) mod 24]+439*[(n+15) mod 24]-1493*[(n+16) mod 24]+715*[(n+17) mod 24]+439*[(n+18) mod 24]+991*[(n+19) mod 24]-941*[(n+20) mod 24]-389*[(n+21) mod 24]+163*[(n+22) mod 24]-113*[(n+23) mod 24]}, with n>=0 [From Paolo P. Lava, Apr 01 2009] MATHEMATICA Nest[Append[#, Total[IntegerDigits[Last[#]#[[-2]]]]]&, {1, 2}, 80]  (* Harvey P. Dale, Apr 21 2011 *) PadRight[{}, 100, {1, 2, 2, 4, 8, 5, 4, 2, 8, 7, 11, 14, 10, 5, 5, 7, 8, 11, 16, 14, 8, 4, 5, 2}] (* Harvey P. Dale, Jan 18 2015 *) CROSSREFS Sequence in context: A077964 A077968 A123958 * A121173 A160159 A283241 Adjacent sequences:  A048569 A048570 A048571 * A048573 A048574 A048575 KEYWORD nonn,easy,nice,base AUTHOR STATUS approved

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Last modified May 27 21:52 EDT 2020. Contains 334671 sequences. (Running on oeis4.)