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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A121390 Sequence generated by the recurrence below begins with exactly seven primes.

Original entry on oeis.org

2, 8607769, 25823309, 222281113118699, 5740034091209256896999, 1275901167133279185594625154673899999, 7323716196358702385046852882006552347670105360888299999999
Offset: 0

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Author

Rick L. Shepherd, Jul 26 2006

Keywords

Comments

This sequence has the smallest value of a(1) for a(0) = 2 and this recurrence such that the first seven terms are primes. The first composite term is too large to include. Note also that each a(n) has Fibonacci(n) trailing 9's (see A121389).

Examples

			a(2) = 25823309 = 2*8607769 + 2 + 8607769 and is prime.

Crossrefs

Cf. A000045, A063896, A121389.

Formula

a(0) = 2; a(1) = 8607769; a(n) = a(n-2)*a(n-1) + a(n-2) + a(n-1).
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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