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 A340389 Number at the apex of Recamán's triangle of primes and squares with n rows. 3
 0, 3, 9, 59, 1669, 147456, 60924257 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Form a triangle of n rows and place a distinct prime or square at each position such that (apart from the bottom row) every number is the sum of the two numbers below it, and such that the number at the apex is as small as possible. REFERENCES Bernardo Recamán, The Bogotá Puzzles, Dover Publications, 2020, Puzzle 3, p. 3. LINKS M. F. Hasler, A340389: Notes and PARI program, OEIS wiki, Aug 2021. M. F. Hasler, PARI code for A340389 (extracted from the above wiki page), Aug 16 2021. Sean A. Irvine, Java program (github) EXAMPLE n=3:     9    4 5   1 3 2 . n=4:         59       23  36     16   7  29   13   3   4  25 . n=5 (B. Mehta):              1669            576  1093         383   193   900      347    36   157   743   324    23    13   144   599 . n=6 (_Sean A. Irvine): _                      147456                   63487   83969               33211   30276   53693           17424   15787   14489   39204       10853    6571    9216    5273   33931   10529     324    6247    2969    2304   31627 . From Bert Dobbelaere, May 11 2021: (Start) n=7:                              60924257                         21861757  39062500                     7799257  14062500  25000000                2736757   5062500   9000000  16000000            914257   1822500   3240000   5760000  10240000       258157    656100   1166400   2073600   3686400   6553600   21961    236196    419904    746496   1327104   2359296   4194304 (End) PROG (PARI) see LINKS CROSSREFS Cf. A089237 (primes and squares). Sequence in context: A105466 A261244 A018504 * A140812 A202210 A243425 Adjacent sequences:  A340386 A340387 A340388 * A340390 A340391 A340392 KEYWORD nonn,hard,more AUTHOR Sean A. Irvine, Apr 24 2021 EXTENSIONS a(7) from Bert Dobbelaere, May 11 2021 STATUS approved

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Last modified January 26 22:05 EST 2022. Contains 350601 sequences. (Running on oeis4.)