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A323509
a(n) = 1 if n = 2^e1 * 3^e2 * ... * prime(k)^e_k, with k = A061395(n) = A001221(n) and e1 >= e2 >= ... >= e_k, with each e1 .. e_k one less than a prime, otherwise a(n) = 0.
2
1, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
OFFSET
1
COMMENTS
Characteristic function for the range of A037019.
FORMULA
a(A037019(n)) = 1.
a(n) <= A322585(n).
PROG
(PARI) A323509(n) = { my(f = factor(n)); for(i=1, #f~, if((primepi(f[i, 1])!=i)||!isprime(1+f[i, 2])||((i>1)&&(f[i-1, 2]<f[i, 2])), return(0))); (1); };
CROSSREFS
Cf. also A323510.
Sequence in context: A185175 A322586 A147612 * A197183 A357382 A295405
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jan 18 2019
STATUS
approved