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A058938 Sum of first n digits of decimal expansion of pi is prime. 1
1, 6, 8, 13, 20, 21, 34, 36, 48, 56, 63, 87, 89, 92, 94, 104, 106, 107, 111, 116, 117, 118, 120, 130, 132, 133, 141, 146, 147, 162, 170, 173, 179, 183, 185, 186, 198, 202, 203, 206, 215, 217, 219, 220, 225, 242, 248, 249, 258, 264, 265, 270, 271, 285, 290, 291 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..56.

EXAMPLE

a(2) = 6 because 3 + 1 + 4 + 1 + 5 + 9 = 23, which is prime.

MAPLE

Digits := 2000: it := evalf(Pi, 2000): for i from 1 to 2000 do a[i] := floor(it): it := 10*(it-floor(it)): od: s := 0: for i from 1 to 2000 do s := s+a[i]: if isprime(s) then printf(`%d, `, i) fi: od:

MATHEMATICA

a = First[ RealDigits[ N[ Pi, 300]]]; Do[ If[ PrimeQ[Plus @@ Take[a, n]], Print[n]], {n, 1, 300}]

Flatten[Position[Accumulate[RealDigits[\[Pi], 10, 500][[1]]], _?PrimeQ]]  (* Harvey P. Dale, Apr 03 2011 *)

CROSSREFS

Cf. A000796, A071117, A133213.

Sequence in context: A190546 A190558 A063188 * A315877 A315878 A101729

Adjacent sequences:  A058935 A058936 A058937 * A058939 A058940 A058941

KEYWORD

easy,nonn,base

AUTHOR

G. L. Honaker, Jr., Jan 11 2001

EXTENSIONS

More terms from James A. Sellers, Jan 14 2001

STATUS

approved

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Last modified April 25 13:31 EDT 2019. Contains 322461 sequences. (Running on oeis4.)