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A111033
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Sum of squares of digits of pi.
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3
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9, 10, 26, 27, 52, 133, 137, 173, 198, 207, 232, 296, 377, 426, 507, 516, 520, 529, 593, 609, 645, 649, 685, 701, 710, 719, 783, 792, 796, 845, 926, 951, 951, 955, 1019, 1083, 1099, 1100, 1181, 1230, 1231, 1267, 1348, 1357, 1438, 1519, 1528, 1577, 1602
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| a(n) is prime for n = 7, 8, 19, 24, 26, ... a(n) is semiprime for n = 1, 2, 3, 6, 13, 18, 22, 23, ... a(n) is a perfect power for n = 1, 4, 18, ...
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FORMULA
| a(n) = sum(i=1 to n) A000796(i)^2.
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EXAMPLE
| a(1) = 3^2 = 9,
a(2) = 3^2 + 1^2 = 10,
a(3) = 3^2 + 1^2 + 4^2 = 26,
a(4) = 3^2 + 1^2 + 4^2 + 1^2 = 27,
a(5) = 3^2 + 1^2 + 4^2 + 1^2 + 5^2 = 52,
a(6) = 3^2 + 1^2 + 4^2 + 1^2 + 5^2 + 9^2 = 133,
a(7) = 3^2 + 1^2 + 4^2 + 1^2 + 5^2 + 9^2 + 2^2 = 137, which is prime.
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MAPLE
| Digits := 120 ;
A000796 := proc(n) floor(Pi*10^(n-1)) ; % mod 10 ; end proc:
A111033 := proc(n) add( A000796(i)^2, i=1..n) ; end proc:
seq(A111033(n), n=1..120) ; # R. J. Mathar, Dec 21 2010
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PROG
| (Sage) A111033 = lambda n: sum(d**2 for d in floor(pi*10**(n-1)).digits()) # [D. S. McNeil, Dec 22 2010]
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CROSSREFS
| Cf. A000796.
Sequence in context: A174042 A156787 A025043 * A123048 A189047 A041170
Adjacent sequences: A111030 A111031 A111032 * A111034 A111035 A111036
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KEYWORD
| base,easy,nonn
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AUTHOR
| Jonathan Vos Post (jvospost3(AT)gmail.com), Oct 05 2005
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EXTENSIONS
| More terms from Vincenzo Librandi, Dec 21 2010
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