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A023689 Numbers with exactly 7 ones in binary expansion. 15
127, 191, 223, 239, 247, 251, 253, 254, 319, 351, 367, 375, 379, 381, 382, 415, 431, 439, 443, 445, 446, 463, 471, 475, 477, 478, 487, 491, 493, 494, 499, 501, 502, 505, 506, 508, 575, 607, 623, 631, 635, 637, 638, 671, 687 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

M. I. Mazurkov, A. V. Sokolov, Nonlinear substitution S-boxes based on composite power residue codes, Radioelectronics and Communications Systems, Vol 56, No 9 (2013). DOI: 10.3103/S0735272713090045.

LINKS

Ivan Neretin, Table of n, a(n) for n = 1..10000

M. I. Mazurkov, A. V. Sokolov, Nonlinear substitution S-boxes based on composite power residue codes, Radioelectronics and Communications Systems, Vol 56, No 9 (2013). DOI: 10.3103/S0735272713090045.

FORMULA

a(n+1) = A057168(a(n)). - M. F. Hasler, Aug 27 2014

MATHEMATICA

Select[ Range[ 127, 704 ], (Count[ IntegerDigits[ #, 2 ], 1 ]==7)& ]

PROG

(PARI) is_A023689(n)=hammingweight(n)==7 \\ M. F. Hasler, Aug 27 2014

(PARI) print1(t=2^7-1); for(i=2, 50, print1(", "t=A057168(t))) \\ M. F. Hasler, Aug 27 2014

CROSSREFS

Cf. A000079, A018900, A014311, A014312, A014313, A023688, A023689, A023690, A023691 (Hamming weight = 1, 2, ..., 9), A057168.

Sequence in context: A137985 A065092 A141916 * A095284 A127579 A107380

Adjacent sequences:  A023686 A023687 A023688 * A023690 A023691 A023692

KEYWORD

nonn,base,easy

AUTHOR

Olivier Gérard

STATUS

approved

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Last modified June 25 20:26 EDT 2017. Contains 288730 sequences.