A181920 - OEIS

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A181920

Length of A185120(n): number of subsequent digits in the decimal expansion of e which form the next longer prime.

1, 2, 25, 90, 456, 608, 1421, 1469

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OFFSET

1,2

COMMENTS

By definition, a strictly increasing sequence.

See A185120 for further comments and explanations.

LINKS

Table of n, a(n) for n=1..8.

EXAMPLE

The decimal expansion of e=exp(1)=2.718281828.... is split into

A185120(1) = 2 of length a(1)=1,

A185120(2) = 71 of length a(2)=2,

A185120(3) = 8281828459045235360287471 of length a(3)=25, etc.

PROG

(PARI) {default(realprecision, 2000); e=exp(1)*.1; for( n=1, 9e9, ispseudoprime(e\.1^n)|next; print1(n", "); e=frac(e*10^n))}

CROSSREFS

Sequence in context: A348064 A069232 A269232 * A123012 A175522 A226418

Adjacent sequences: A181917 A181918 A181919 * A181921 A181922 A181923

KEYWORD

nonn,base

AUTHOR

M. F. Hasler, Apr 01 2012

STATUS

approved