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.

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A173620 Main diagonal of array A[k,n] = n-th Fibonacci number which becomes prime when digits (base k) are reversed.

Original entry on oeis.org

2, 5, 13, 8, 89, 233, 233, 1597, 39088169, 121393, 4052739537881
Offset: 1

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Author

Jonathan Vos Post, Feb 22 2010

Keywords

Comments

First row is the prime Fibonacci numbers A005478 (as reverse of unary does not change the number). 10th row is A173268. Computations mostly by R. J. Mathar after first few terms from Jonathan Vos Post. Mathar also notes that omitting the base=1 row, gives the diagonal: 3, 5, 5, 55, 34, 89, 610, 1346269, 75025, 2504730781961, 14930352. The array begins:
===============================================================================
....|.n=1.|.n=2.|.n=3.|.n=4.|.n=5.|.n=6.|.....n=7.|...n=8.|........n=9.|......n=10|
k=1.|..2...|..3.|...5.|..13.|..89.|.233.|....1597.|...28657.|...514229.|.433494437|
k=2.|..3...|..5.|..13.|..34.|..55.|.233.|.....377.|.....610.|.....2584.|...4181657|
k=3.|..2...|..5.|..13.|..21.|..55.|.233.|.....987.|...28657.|....75025.|.433494437|
k=4.|..2...|..3.|...5.|...8.|..13.|..89.|.....233.|....1597.|.....4181.|....514229|
k=5.|..2...|..3.|..13.|..55.|..89.|.233.|...28657.|...21393.|...514229.|...9227465|
k=6.|..2...|..3.|...5.|...8.|..34.|.233.|14930352.|63245986.|701408733|...86267571272.
k=7.|..2...|..3.|...5.|..13.|..21.|..89.|.....233.|....1597.|.....4181|....2865
k=8.|..2...|..3.|...5.|..13.|..89.|.233.|.....610.|....1597.|.....2584|.....4181
k=9.|..2...|..3.|...5.|..13.|..21.|.987.|....1597.|..346269.|.39088169|701408733
k=10|..2...|..3.|...5.|..13.|..34.|.377.|....1597.|...10946.|....75025|121393|
k=11|.2..3....5.....13.....55......89.......233.........1597..956722026041.2504730781961.4052739537881
k=12|.2..3....5.....13.....21......89......1597......1346269......3524578.......5702887.....14930352.4052739537881.
k=13|.2..3....5.....55.....89.....233.......377.........1597........75025.
k=14|.2..3....5.....13...2584....4181..39088169.365435296162.956722026041.
k=15|.2..3....5.....13....233.....377......1597.........4181.........6765.........75025.......121393....701408733.956722026041

Crossrefs

Cf. A000040, A000045, A001605, A004086, A115347, A173268.
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