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 A111236 a(1)=a(2)=a(3)=a(4)=1. For n >= 5, a(n)= (a(n-1)+a(n-2)) * (a(n-3)+a(n-4)). 0
 1, 1, 1, 1, 4, 10, 28, 190, 3052, 123196, 27522064, 89625932920, 11318569384820032, 312907271203608153807520, 28053218967767813941001154374119168, 317524819653692484884273872549799784105586335582976 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 LINKS MATHEMATICA RecurrenceTable[{a[1]==a[2]==a[3]==a[4]==1, a[n]==(a[n-1]+a[n-2]) (a[n-3]+ a[n-4])}, a[n], {n, 20}](* Harvey P. Dale, Aug 08 2011 *) PROG (PARI) a(n)=if(n<5, 1, (a(n-1)+a(n-2)) *(a(n-3)+a(n-4))) (Klasen) CROSSREFS Sequence in context: A243600 A239577 A008995 * A164361 A006907 A305204 Adjacent sequences:  A111233 A111234 A111235 * A111237 A111238 A111239 KEYWORD easy,nonn AUTHOR Leroy Quet, Oct 28 2005 EXTENSIONS More terms from Lambert Klasen (lambert.klasen(AT)gmx.net), Oct 31 2005 STATUS approved

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Last modified August 8 08:27 EDT 2020. Contains 336293 sequences. (Running on oeis4.)