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A155577 Intersection of A154777 and A154778: N = a^2 + 2b^2 = c^2 + 5d^2 for some positive integers a,b,c,d. 1
6, 9, 24, 36, 41, 54, 81, 86, 89, 96, 129, 134, 144, 150, 164, 166, 201, 214, 216, 225, 241, 246, 249, 281, 294, 321, 324, 326, 344, 356, 369, 384, 401, 409, 441, 449, 454, 486, 489, 516, 521, 534, 536, 566, 569, 576, 600, 601, 614, 641, 656, 664, 681, 694 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Subsequence of A155567 (where a,b,c,d may be zero).

LINKS

Table of n, a(n) for n=1..54.

PROG

(PARI) isA155577(n, /* optional 2nd arg allows us to get other sequences */c=[5, 2]) = { for(i=1, #c, for(b=1, sqrtint((n-1)\c[i]), issquare(n-c[i]*b^2) & next(2)); return); 1}

for( n=1, 999, isA155577(n) & print1(n", "))

CROSSREFS

Cf. A000404, A154777, A092572, A097268, A154778, A155716, ...

Sequence in context: A295726 A034718 A215528 * A084431 A176498 A142877

Adjacent sequences:  A155574 A155575 A155576 * A155578 A155579 A155580

KEYWORD

easy,nonn

AUTHOR

M. F. Hasler, Jan 25 2009

STATUS

approved

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Last modified April 22 19:11 EDT 2021. Contains 343177 sequences. (Running on oeis4.)