cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A235397 The first term of the least sequence of n consecutive Moran numbers.

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%I A235397 #29 Apr 30 2020 14:26:40
%S A235397 18,152,3031,21481224,25502420,4007565001480,2196125475223740,
%T A235397 905295493763807066010
%N A235397 The first term of the least sequence of n consecutive Moran numbers.
%C A235397 A number n is a Moran number if n divided by the sum of its decimal digits is prime.
%C A235397 From _Amiram Eldar_, Apr 25 2020: (Start)
%C A235397 _Jens Kruse Andersen_ found that a(7) <= 2196125475223740 and a(8) <= 905295493763807066010 (see Rivera link).
%C A235397 Since Moran numbers (A001101) are also Niven numbers (A005349), this sequence is finite with no more than 20 terms (see A060159). (End)
%C A235397 a(9) <= 270140199032572375590810. - _Giovanni Resta_, Apr 30 2020
%H A235397 Giovanni Resta, <a href="http://www.numbersaplenty.com/set/Moran_number/">Moran numbers</a>
%H A235397 Carlos Rivera, <a href="https://www.primepuzzles.net/puzzles/puzz_728.htm">Puzzle 728. Consecutive Moran numbers</a>, The Prime Puzzles & Problems Connection.
%e A235397 a(6) = 4007565001480 because
%e A235397 4007565001480 = 40 * 100189125037,
%e A235397 4007565001481 = 41 * 97745487841,
%e A235397 4007565001482 = 42 * 95418214321,
%e A235397 4007565001483 = 43 * 93199186081,
%e A235397 4007565001484 = 44 * 91081022761,
%e A235397 4007565001485 = 45 * 89057000033.
%o A235397 (PARI) isA001101(n)=(k->denominator(k)==1&&isprime(k))(n/sumdigits(n))
%o A235397 a(n)=my(k=n); while(1, forstep(i=k,k-n+1,-1, if(!isA001101(i), k=i+n; next(2))); return(k-n+1)) \\ _Charles R Greathouse IV_, Jan 10 2014
%Y A235397 Cf. A001101, A060159, A085775.
%K A235397 nonn,hard,base,fini,more
%O A235397 1,1
%A A235397 _Carlos Rivera_, Jan 09 2014
%E A235397 a(7)-a(8) from _Giovanni Resta_, Apr 27 2020